giant panda

for example I haven't listened to the commentary on 4/5 of my DVDs and it would be cool is there was a place that rated them so I know what ones are worth hearing. same for behind the scenes and other extra features. I know this idea is ridiculous but it's worth a shot

Numes

For commentaries specifically, I frequent http://www.ratethatcommentary.com. Personally, I love commentaries so much that I listen to all of them no matter what

For all other special features, most DVD/Blu-Ray review sites (including DVDTalk) have separate areas in the review that specifically talk about the special features. http://www.dvdcompare.net is excellent on specifically parsing the special features, but does not have any sort of user rating like you are asking about.

Ash Ketchum

This is a very good question. I tend to be reluctant to listen to commentaries unless they involve people I revere and admire very much. And not many of them are around anymore to do commentaries. I'm not sure how I wound up listening to the few commentaries I have listened to, except that I might have read recommendations of them in online forums or print publications. A guy on another web forum urged us to get THE LONGEST YARD (1974) DVD for Burt Reynolds' commentary. So when I found it on sale somewhere for $10 or so, I picked it up and damned if he wasn't right. The Reynolds commentary is quite possibly the best one I've ever heard. Other good ones I've listened to: John Philip Law on DANGER DIABOLIK (1967) and Raquel Welch on MYRA BRECKENRIDGE (1970). Ones I have that I need to sit and listen to are THE MAGNIFICENT SEVEN (1960) commentary featuring some of that great cast, and WINCHESTER '73 (1950), in which they use a James Stewart interview as the commentary track.

giant panda

thanks guys, that link is exactly what I'm looking for. I'm glad to see a bunch of movies I own in the top 100, and the commentaries I have listened to seem to be rated accurately