The best science fiction community: SFF Chronicles
For all your second-hand book needs: Abebooks
The Encyclopedia of Science Fiction
The Internet Speculative Database
The Galaxy’s Greatest Comic: 2000AD
Starfarer Science Fiction, a brilliant science fiction site from New Zealand run by Mike Bikerdike. Rapidly becoming a brilliant resource for science fiction fans.
Adam Whitehead’s Hugo Nominated blog The Wertzone.
So many board games: Board Game Geek