Futurama-All 3 seasons
X-men
X2
Usual Suspects
Seven
Fight Club
Lord of the Rings
Matrix
Indiana Jones movies
Kurasawa's Criterion movies
Pitch Black
Aliens
Abyss
Star Trek 2, 4, 6, and most of the Next Gen movies
Lilo & Stitch
Pixar flicks
T2
Embrace of the Vampire
Man, I thought I was behind in my DVD's looking at some of the other lists, but when you look at it on the screen I guess I'm just as much of a movie freak as anyone here.
Wow, I can't believe no one had the Matrix. That is one of the first DVDs with a ton of extra features on it. If we are talking "must haves," it has got to be on the list (none of the sequals though, even though I liked them).
Terminator 2 is another really great DVD.
Momento is really good DVD to have, but it might not make the "must have" list.
Actually, Fox has placed the two disc edition of Fight Club and quite a few other titles on moratorium (meaning that they are out of print) quite some time ago. If you're able to find the two disc set then count yourself lucky.