If you have no interest in how a movie is made, or in why a director chose to shoot a scene a certain way, or what an actor's inspiration was when taking on a role, then you won't be interested in commentaries or interviews. Personally I love that sort of stuff.
That being said, a lot of commentary tracks suck because the commentators have no personality what so ever, and fall silent and watch the movie for 5-10 minute stretches before saying something. I tend to fall asleep to those.
Fight Club Special Edition (2-Disc set, comes in a tin case): Tons of legitimately interesting commentary tracks for this movie. Off the top of my head I think I remember 4 seperate commentary tracks, and I can defintely remember two that were fantastic and one that I really liked.
Pulp Fiction Collector's Edition: Surprisingly, no commentary at all on this one (rumor goes that by the time Miramax was working on this DVD set, Tarantino was sick and tired of talking about the movie, so he refused), but instead you have the option to turn on this trivia track that run as subtitles during the movie, and serves as some very cool commentary to a classic movie. Combine that with a couple of TV specials (a Siskel & Ebert special, and an hour long interview with Tarantino), a shit ton of trailers and TV spots from around the world, and a bunch of really interesting articles from critics about the movie.
Jackie Brown Collector's Edition: Almost note for note, the exact same extras as the Pulp Fiction set, but tailored for Jackie Brown. I throw this in, because in my opinion it's almost criminally overshadowed by it's big brother (Pulp Fiction). Granted that PF is overall a better movie, it does not take away from the absolute excellence of Jackie Brown.
The Miramax Collector's Series edition of Clerks also has a great commentary track, where Smith and company talk about how they got the movie off the ground and the difficulties of following through and finishing the indie project. It also tends to be funnier than the movie itself many times, thanks to audio cameos by several people during his taping, including the ever popular Mewes, who supposedly shows up drunk (he sure sounded like it).
On the same note, the Clerks Uncensored DVD set which contains all 6 finished episodes of the Clerks cartoon has a commentary track for each episode, and each one is hilarious and pretty informative if you don't get all the cross-referential in-jokes laced throughout each episode.
I've also heard that pretty much everything by View Askew (Kevin Smith movies) have excellent commentary tracks, unfortunately those two are the only ones I own.
I'd jot down more than just the usual suspects (Smith and Tarantino) if I could, but as of yet, my DVD library isn't all that great yet. I'll leave it to others to hopefully clue you in on some lesser-known titles' extras.
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