The ones I rewatch all the time are
Jackass
Viva La Bam
The Wildboys

My most watched sets:

1) Mr. Show
2) Futurama
3) Arrested Development
4) Family Guy S1-3
5) The Office Uk
6) Extras

The top 2 are easy and it's not even close, tough call for my third:

1. Babylon 5
2. Sports Night
3. The Adventures of Brisco County, Jr./Veronica Mars

1. Entourage
2. Weeds
3. The Family Guy

1) Power Rangers
2) Red Dwarf
3) Tales from the Crypt

Power Rangers is number 1 because there are so many damn episodes. Season 1 had 60.

For me its...

1. The Simpsons
2. Sabrina, The Teenage Witch
3. Seinfeld

After seeing everyone's list, I feel like the "oldie" around here. No love for classic television series from anyone, really. I'm surprised! I guess this is truly the moment I become old, when I see what everyone else is doing, and think that they don't appreciate the distant past!

1. Mission:Impossible S1-3 (Landau/Bain years)
2. Big Valley S1-2 (well, half of S2)
3. U.F.O. (of course!)

Was really looking forward to the Wild Wild West but S2 was so damn silly that I gave up on it. Have been tempted to start on Gunsmoke but I know they'll never finish it so I'm holding off.

1.) LOST
2.) X-Files
3.) Battlestar Galactica

Twilight Zone
Columbo
X-Files

Twilight Zone and Columbo, for me, have so much rewatch value... it is insane. I've watched some Columbo episodes 7-8 times, easily. Twilight Zone, same deal. There's some episodes of TW I can revisit over and over.

-beebs

1. South Park
2. The Simpsons
3. Futurama & American Dad are tied for 3rd

1.The Shield (Seasons 1-6)
2. Firefly
3. Friday Night Lights (Seasons 1-2)

I was thinking about doing a top 5, but those turn into people posting 10 real quick. Plus I figured most people will probably have three shows that are 'comfort food' that can get replayed no matter what the mood.

Same for me when I started the thread. Top 2 were easy. Number three was a hard choice. I put Band of Brothers, but like, you Veronica Mars would probably be in the running. At least a tie for third. What's amazing is that I just watched VM for the first time back in February. I watched all three seasons in about a months time and now I'm already through the first two seasons for a second time.

01.Firefly
02.Veronica Mars
03.Weeds

The ones I rewatch the most are usually single season shows with a self contained ongoing story.

1. Wonderfalls
2. My So-Called Life
3. Firefly / Freaks and Geeks

And if anime counts, Serial Experiments Lain would be #1.

I'd love to rewatch some longer running shows; Buffy, Xena, Six Feet Under, etc. but once I start with one, I feel I should watch them all. And I've got too much backlog for that- I'm currently making my way through 4 seasons (sorry, series) of Doctor Who for the first time- and have a dozen or more other shows to watch after that.

The Office (UK)
The Simpsons (seasons 1-8)
Twin Peaks
Homicide: Life on the Streets
Fawlty Towers

Arrested Development
Seinfeld
Frasier

Most Watched..

Columbo
All in the Family
Seinfeld

Watched alot..

Twilight Zone
Rockford Files
Married With Children
Roseanne
The Waltons
3rd Rock from the Sun
Curb Your Enthusiasm
Dukes of Hazzard
King of the Hill
Fantasy Island
Welcome Back Kotter
The Honeymooners

Like others said before these shows and others are so much better than what's available these day's, tho there are 2 really great shows on the airwaves today that i really enjoy and do own dvd's and watch quite a bit of they are..

Boston Legal
Two and a half Men

Doctor Who
Star Trek: Voyager
Futurama

1. I Love Lucy - It's the only TV on DVD that I watch frequently
2. Home Improvment
3. Project Runway

1. X-Files
2. The Shield
3. The Wire(Season 2 is the best.)
4. Adventures of Brisco County Jr

1. M*A*S*H
2. How I met your Mother
3. Hogan's Heroes

1. Buffy
2. 30 rock
3. Spaced

A very close 4th would be Arrested Development.

Three is too tough

1. M*A*S*H
2. Family Guy
3. Xena Warrior Princess
4. Star Trek TOS
5. Mary Tyler Moore Show
6. Taxi
7. Starsky & Hutch
8. Buck Rogers
9. Planet of the Apes
10. Gilligan's Island/Three's Company (tie)

I don't watch new network shows save Family Guy.

Kolchak - The Night Stalker
Planet of the Apes
The Addams Family
and The Office (US)