Every 10 minutes of the Delta Force commentary on Black Hawk Down Deluxe, I said aloud to myself "Wow." Curt Schilling's cousin is such a badass when he walks down the street people say "Wow, that guy's a huge badass."

Both Anchorman commentaries (one on the rated and one on the unrated) are hilarious. Also great is the commentary on Dill Scallion, but since it seems I'm the only person who owns that DVD I can't really call this a recommendation.

From my post on the original thread:

I'll second any of the Conan O'Brien commentaries on the Simpsons.

I'll also second Cannibal: The Musical. Absolutely Hilarious.

Also, in no particular order:
- Any Simpsons Commentaries
- Any Futurama Commentaries
- Any Babylon 5 Commentaries, there is an excellent balance between the JMS commenatires which are very informative, and the Actor/Actress commentaries which are just a lot of fun. I WISH THERE WERE MORE!!!
- Guillermo del Toro Commentary on the Director's Cut of Hellboy. Update, his Blade II commentary is also excellent.
- Any Stargate SG-1 Commentary with Peter DeLuise (The others are great too, but Peter has that hint of comedy that is enjoyable
- Any Nicholas Meyer commentary (ST:II, ST:VI) I haven't listened to the Time after Time Commentary yet, but I'm sure it will be great.
- Any Trey and Matt Commentary - Even if it is only 5 minutes
- I liked the scene specific commentaries on True Romance, it's been a while, but I remember those to be pretty informative
- I liked the Will Ferrell Commentary in Elf because he was actually just being "himself" and not in character.
- This is Spinal Tap Commentary (in character). I would love to listen to the commentary from the Criterion, but I don't feel like plopping down $100+ right now
- Both Goodfellas commentaries
- Gangs of NY commentary with Scorsese. I wish he would have actually talked to the movie as it was playing, but it was still an excellent commentary even if it wasn't directly talking to the movie as it was playing.
- Mr. Show commentaries. I was a little annoyed in the first DVD release where they would always go into some random character, but they seemed to stop that for the subsequent releases.
- Se7en commentary with Fincher and Pitt. I haven't listened to to the other commentaries, or the commentaries from Fight Club, but after listening to one Fincher commentary, I can guarantee that I will enjoy any others. Morgan Freeman did disappoint me in the Se7en commentary and the Robin Hood commentary.
- Mallrats. I have to give it props because it was one of the first DVD's I ever owned and the first commentary I ever listened to. I remember a lot of ribbing of Afleck. Good stuff.

The Spinal Tap in-character commentary.

Any Kevin Smith one.

Some of my favorite commentaries are:

Kentucky Fried Movie
Used Cars (whats Kurt Russell on?)
Re-Animator - cast

The one I recommend the most is Jack-O. The movies pathetic but the commentary is required viewing. If you can rent it do so now!

Tarantino shares a commentary track with director Jack Hill on Switchblade Sisters. QT is his usual hyper self, and Hill is amiable and very laid back; I found myself wishing that their opposite types of personalities would make for a more entertaining commentary. A lot of times QT will take off on some bit of trivia that JH isn't familiar with and the momentum of the track stalls.

Much better for me is Hill's commentary on Coffy with a lot of insights into low-budget filmmaking. I don't know if he has any other solo tracks but they would probably be a good listen.

I love the Roger Kumble & crew commentary on CRUEL INTENTIONS - it remains one of the most enjoyable commentary tracks I've listened to after 5 years of reviewing DVDs.

As for more recent ones, all five commentary tracks on the new LOST box set are worth your time...

Stephen Prince's commentary on Red Beard. Just about any Werner Herzog commentary. He's hilarious.

Quentin Tarantino also does commentary on the Reservoir Dogs 10th Anniversary SE DVD, but he is joined by several other people as well.

Any of the commentaries from the new Fox Film Noir series are very good as well.

This is by far my favorite commentary. He is extremely funny, but he appropriately turned off the funny during the drawn out, brutal rape scene. This is truly a DVD worth owning for the commentary alone.

John Carpenter/ Kurt Russell - The Thing

Walt Disney and staff - Bambi (well, sort of - those with the disc know what I mean!)
Bruce Campbell - Bubba Ho-tep

Umberto Lenzi/ John Morghen - Cannibal Ferox (makes a rubbish, unpleasant movie into a laugh riot as Morghen basically attacks the film and director throughout)

Renny Harlin/ Sam Jackson - Deep Blue Sea

Several of the Universal monster titles have decent commentaries, but Weaver's stands out for me. He manages to squeeze an incredible amount of information into nearly every minute of the film's running time, while still being very funny - even somewhat irreverent - on occasion. Note the remark about the "view" from the telescope on an upper level of the Talbot house.

A lot of the obvious ones have been mentioned, but I didn't see anyone mention Shattered Glass. I thought that was a really good one (enough for me to write a mini-review of it on my ratethatcommentary.com site...)

The top 25 list on there is also a pretty good representation of which commentaries people are most into. Probably most (if not all) of those have been mentioned here already.

And then you have some like Anchorman which just have the strangest mix of people that love it and people that hate it. I might have to listen to it one of these days to find out what the deal is with it. The 2 reviews on my site are both negative, but I've seen other people (including in this thread) say that they love it. You can see a little of that in the vote distribution. I guess, like with many things, it's just a matter of taste?

Not including the popular ones already mentioned many times (I highly recommend those as well though!) I'm a commentary addict and actually get to listen to them in work as research, so I'm constantly getting a fix...
I hate to shill, but I also made a page on Amazon with my favorite commentaries on classic films with a few details if anyone's interested in that. Great commentary tracks on classic films

My (none-mentioned) favorite is The Goonies, which is a video commentary with all the goonies grown up and Richard Donner! Donner is great at commentaries in my opinion, the ones I've listened to & liked are Superman & The Omen.

The commentaries on the Fox Film Noir collection have all so far been really good, both with info and just keeping it interesting. The TCM Buster Keaton set has terrific ones on The Cameraman and Spite Marriage. The Shawshank Redemption special edition has Frank Darabont doing a fantastic one, and Martin Scorsese consistently does very useful ones (the best is GoodFellas, and the commentary with the officer and the man Liotta played is amazing and the best on the disc.)

I also found Michael Moore's commentary on Roger & Me at turns touching, sad and funny. Also the Blake Edwards/Julie Andrews one on the film version of Victor/Victoria is very charming (you can really tell they respect and admire as much as they love each other), Blake is also good on The Pink Panther. Oh, and my latest high-rated one is Joel Schumacher on The Lost Boys special edition. I'm not really a fan of his but he knows how to do a good commentary.

The Goonies
Clerks. 10 Ann.
Rocky SE
Speed Producer/Writer commentary
One Crazy Summer
Silent Night, Deadly Night Part 2
Fight Club Fincher/Pitt/Norton/Carter
Jason Goes to Hell
Police Academy (A gulity pleasure)

Swingers commentary is good. Jon Favreau and Vince Vaughn talk a lot about making this film on a really low budget and the path they took to getting it financed in the first place after rejecting huge budgets from studios that insisted they rewrite and recast. They also use a light pen to draw on the screen and circle things they're talking about. Lots of fun.

The Boogie Nights commentaries are great, as are the Hard Eight commentary tracks. The Hard Eight tracks especially get into the crap that a first time independent director faces, and P.T. Anderson had a real nightmare with that film and gets his revenge by getting to tell his story in these tracks.

Almost Famous (Untitled cut).

The commentaries on the early Friends episodes (only watched the first three season sets). Full of stories and interesting discussion about putting on a sitcom.

Terminator 2 (Extreme edition).

I'm gonna raise this post from the dead,since I've never been a fan of commentaries unless,they were Evil Dead,ED2,AOD,or Kevin Smith I never gave them much of a chance.
Recently I've watched the following...
Dodgeball:Unrated-This sucks,its a "joke" commentary but its not funny
Dodgeball:Theatrical-More serious,but not that good either
Night of the Living Dead Commentary w/Mike Nelson-Funny at times,most comments were hit or miss
Night of the Living Dead Cast "Zombie Party"-Good commentary,tho sometimes you didn't know who was talking
Night of the Living Dead-Crew "Zombie Masters"-Good commentary,and you always knew who was talking the 4 of them have very distinctive voices.
Red Eye-Good production notes moderatly interesting commentary
Shaun of the Dead-Both Commentaries were excellent,the Pegg/Wright being my favorite of all time. The Cast was very good too,and the mention of David & Di being
Brittany Spears & Harry Potter in both was very funny.
Waiting:Expanded Telestrator-I liked this alot to. a 94 Minute Movie extended to 130 minutes for a commentary,not to mention the countless Selective Scene Cast Video Commentaries on the Waiting Disc. Waiting was good,but good enough to earn a all-together 4-Disc Set(w/Exclusives included),no,but the disc is my favorite to come this year so far,and there's been movies I love come out but the Waiting Set was excellent. Anyway....

I plan on watching more,commentaries have grown in interest alot.
Oh and I know this is a Favorite Commentary thread,but I didn't want to start up a new thread

the best of the best:

Amityville II & III
Basic Instinct (Verhoeven makes me giggle. Can’t say why.)
Boy Who Could Fly, The
Coffy
Cronenberg'scommentaries (I always come away from it having learned something new )
Election
Escape from new york/the thing/big trouble in little china
Goonies, The
Halloween II
Heathers
Hell night
House
I spit on your grave (one of the most funniest and most informative...ever!)
Joe Dante's
John Waters... Always fun.
Lord of illusions
Nightmare on elm street part 1
Phantasm
Re-animator & bride of re-animator
Romero's Commentaries are all superb, full of insight and fun to listen to.
Safe
Soul man (!)
Stuff, The
Suburbia (Penelope Spheeris is pretty funny on this)
Tenement (it's the place to be!)
To Live And Die In L.A.
Unmarried Woman, An
Valley girl
Waking The Dead
Warlock moon
Wayne's World

Oh and of course the Bruce Campbell stuff.

Not only is he funny and witty, he actually knows what he's talking about. I think even moreso than the likes of the actual directors of the respective films. He seems to have kept track of everything and stored it away, waiting to unleash it when need be. Intelligent and a barrel of fun. He is the man.

Harold Ramis on Groundhog Day SE

Out of Sight CE, w/ director and writer

Both great and replayable

Alien "Quad"rilogy - I appreciated the honesty on these tracks (and the featurettes as well). There wasn't much butt kissing which is surprising.
Bring It On - One of the few solo commentaries that I found enjoyable.
40 Year-Old Virgin - Can't believe they got as many people as they did (nearly the entire cast, with the director, except Keener). As far as I could tell, I believe they were in the same room. They even had the e-bay store kid...
Gladiator - Both the theatrical and extended version commentaries were good. I did enjoy the back and forth talk between Crowe and Scott.
Jerry Maguire - The video commentary with Cruise, Gooding, Zellweger and Crowe is fun to watch.
Ocean's 11 - Both track, the one with Soderbergh and writer Griffin; the other with Pitt, Damon and Garcia.
Old School - Enjoyed listening to the Ferrell, Vaughn and L. Wilson.
Pirates of the Caribbean - Listened to this with head phones, could've sworn I heard a bong in there somewhere, lol.
Rules of Attraction - Carrot Top, makes paying $5.50 worthwhile
Sideways - It truly sounds like Giamatti and Church are good friends... Probably the most enjoyable commentary, you can't help but to smile.
The Simpsons - Most of the Simpson commentaries.

Others:
Harold and Kumar Go to White Castle, American Pie movies, Meet the Parents (unique in that DeNiro and the producer were in one location and Stiller and Roach were in another...), SWAT (enjoyed the cast part, wished it had been more), Speed, Two Weeks Notice, Blade: Trinity (cast), LotR (all)

I'm a big fan of the commentaries done by the Peckinpah experts (Redman, Weddle, Simmons and Seydor) on various releases, particularly the Legendary Westerns collection. In some cases, I've heard the commentaries more than watched the films themselves!
I also love the Evil Dead trilogy commentaries for their humor and behind the scenes info.

2nd the Alien Quadrilogy, especially James Cameron's... also 2nd the Cronenburg commentaries, very informative!

Thrashin!

My favorite is probably still Ridley Scott's original commentary on the 20th Anniversary Edition of Alien. It was incredibly informative and very interesting to listen to. I like that he managed to blend together all the highly technical stuff about the production for the film techies, the conceptual stuff for all the hardcore fans of the series, the inside stories and anecdotes for the casual fans, as well as his own personal feelings and reflections about the film and the franchise for those who'd just like to pick the brain of one of the better filmmakers working today.