Books: Penny Arcade
Penny Arcade, at least to the video and PC gaming community (and I ain't talking gambling), is pretty much the most popular webcomic around. They've actually gone on to release several collections of their work; the latest book just hit stores.
Unlike a lot of webcomics, PA is completely, truly, and utterly about gamers and geeky fandom. If you're the kind of guy who can appreciate that Klingon has no word for "hello," or the kind of gal who knows how to get to the Minus World in Super Mario Bros., or just the kind of person who wishes Wizards of the Coast didn't try to milk people for all they were worth (D&D Edition 3.5 - AKA we think you guys will pay $20 for the same content).
If that last paragraph didn't make any sense at all, kindly disregard this whole post. :-)
My favorite PA series of strips is their parody of "Dead Rising"/"Dawn of the Dead," entitled "Armadeaddon." Here's the beginning of that epic tale: