My Top 8... not in order
Hackers - A classic
Tron - This movie use the real computer terminology and hacking is like riding cool plastic bike
WarGame - Wardialing!
The Net - funny
Swordfish - Great special effect and some bimbo do nasty trick ;-)
Ennemy of the state - Big Brother is Watching you ;-)
Antitrust - The evil empire of Microsoft inspire movie writers
The Matrix - Hack the Matrix ;-)