Lots of folks are talking about this ridiculous list of the "Top Twenty Novels for Geeks" that resulted from a Guardian survey. And yeah, pretty much anybody who looked at the list was immediately struck by the complete absence of any books by women. That's not the list's only deficiency (not by a long shot), but it's the one that's easiest to correct with our own lists, as folks are doing in this post at Velvet Threads.
Clearly, the list below is incomplete. And I'm not saying that these are (necessarily) the best books by these authors or that the books are, in and of themselves, geeky. But I definitely think you're a geek if you've read 'em all. And if you haven't read 'em all, you should get to it, 'cause your geek street cred is weak!
Alphabetical by author, natch:
Wild Seed by Octavia Butler
Synners by Pat Cadigan
Downbelow Station by CJ Cherryh
Heritage of Hastur by Marion Zimmer Bradley
Shards of Honor by Lois McMaster Bujold
Rats & Gargoyles by Mary Gentle
Queen City Jazz by Kathleen Ann Goonan
Slow River by Nicola Griffith
Brown Girl in the Ring by Nalo Hopkinson
Life by Gwyneth Jones
A Wizard of Earthsea by Ursula K. LeGuin
Stranger Things Happen by Kelly Link
Dragonflight by Anne McCaffrey
China Mountain Zhang by Maureen McHugh
Golden Vanity by Rachel Pollack
Natural History by Justina Robson
Harry Potter and the Sorceror's Stone by JK Rowling
The Sparrow by Mary Doria Russell
Frankenstein by Mary Shelley
The Snow Queen by Joan D. Vinge