I second Snow Crash, and add The Diamond Age by the same author, and also anything by William Gibson is pretty much guaranteed to be Cyberpunk and good, except perhaps his most recent: Pattern Recognition.
Another awesome novel that is also special because it's a source of inspiration for BLAME! is Feersum Endjinn by Iain M. Banks.

Novels: definitely Feersum Endjin by Iain M. Banks, in fact most of the Culture novels would qualify as they deal a lot with megastructures, Consider Phlebas in particular; William Gibson (definitely Neuromancer); Bruce Sterling (see The Artificial Kid); John Brunner (Stand on Zanzibar; The Shockwave Rider); Neal Stephenson's books are often cyberpunkish, but try The Diamond Age instead of Snow Crash, as the latter is actually a satire of cyberpunk so you have to be familiar with the genre to get the jokes. Also, Great Sky River by Gregory Benford.

Movies: THX1138, Bladerunner, The Fifth Element, I Robot.

Check this thread out as well:

http://heeen.de/blame/viewtopic.php?t=100

I recently saw this movie () that also goes by the name »Hellevator« (aside of some others). It's an either-love-or-hate-movie (and it's really low budget).

I loved it and it reminded me of Blame! somehow.

That may be because of the claustrophobic atmosphere and because the »world« is made of different levels, too.

Anyway, take a look. If you liked »Cube« (the first one) you probably it. Or hate it.

I noticed how in The Great Sky River, the main character is named Killeen.

Inspiration for Nihei?