FOLDOC and Babylon define terms. Babel spells out acronyms and abbreviations. Look it up at the WhoIs database, Uwhois, and Reverse DNS Lookup.
Geek sites: CNET, Geek.com (of course), Hardware Zone, Phrack, Slashdot, ZD-Net, and 2600. The Hacker Handbook.
Favourite utilities and games (may be zipped, so you may need this): Core FTP, Font Library, Palm Boulevard, Palm Gear, pdf995, PGP, Slice, and Tetris Lite. I've also compiled some useful Web Tools.