Where I buy parts - Various places
A great magazine for builders - Nuts & Volts
KitParts - Hard to find parts from N3LLL.
HobbyTron Kits - Interesting kits (xmit/rcv, antennas, packet, etc.)
Electronic QSLs - Nice and mostly free
An HF receiver on the web (too cool) - Listen to HF online (I hear there is another one of these somewhere, anyone know where?)
Track satellites - Track satellites with nothing more than a Web browser. If you have a rig that can work 10m and 15m (like all the modern HF rigs) you can work the RS satellites on their next pass! Currently not working :-(
Another satellite tracking page - Another tracker courtesy of NASA.
Web-based DX cluster (try it!) - Find out who's working the DX and where it is
Yahoo's Ham Radio Links - Yahoo!
The local ham radio club, CLARC - The very energetic CLARC club
Another great projects page - My favorite page of things I mean to get around to building
A very well done digital communications page (RTTY, PACTOR, etc.) - Ran across this one the other day
Free Spice - From Linear Technology. Nice!