I'm not very well read in sci-fi, fantasy, graphic novels, and other favourite genres of "geeks". But I'm writing a character who is a computer programmer and who is really into that whole world, and so I need to read up on all these genres I've missed! Which books would you say are the quintessential "must read" books for people who want to be a part of that subculture? Which ones are most accessible to people who aren't hardcore into fantasy/sci-fi, and which ones are the real litmus test of one's nerditude?