[techweenie]

2 Days in the Valley (Terry Hatcher/Charlize Theron catsuit catfight!)
American Splendor
Barton Fink (not for anyone who doesn't know what writer's block is)
The Big Lebowski (psychedelic noir)
Blade Runner
Blood Simple (second best 'first film' ever)
Blow
Blue/White/Red trilogy
Bound (Gina Gershon... Meg Tilly... leather...)
Boy and his Dog (classic must-have)
Buckaroo Banzai (fringe-y cult wannabee)
Cat People (82)
Clockwork Orange
Dark City (great stuff)
Dark Star (see where Alien came from!)
Das Boot
Disco Pigs
Donnie Darko (best 'first film' since Citzen Kane)
Earth Girls are Easy
Eyes Wide Shut
Fight Club (must-have)
Fifth Element
Forbidden Planet (there's a reason they haven't remade this)
Ghost in the Shell (my fave anime)
Invaders from Mars (50s)
Lost Highway
The Man Who Wasn't There (underrated Coen)
Mars Attacks
Monty Python and the Holy Grail
Motorama (another wannabee cult classic)
Mulholland Dr (Naomi!)
Pi ('nother great 'first film')
The Rocky Horror Picture Show
Repo Man (the life of a repo man is intense)
Rumble Fish
The Rutles (you have to see it once)
Sin City (eye candy)
They Live (trashy fun)
Zachariah (Siddhartha in the wild West with electric guitars!)

and nearly 100 other, more mainstream choices...

Worth seeing, if not owning:

Forbidden Zone