NeHe Productions (OpenGL)
For some reason you can't get to NeHe's front page with GameDev.net. Here's your portal.
Gamasutra
They have lots of good stuff on here, but I go for the feature columns. I really enjoy Earnest Adams' works.
Game Developers Search Engine
Can't find what you need on GameDev.net or Gamasutra? Try here. I've found loads and loads of stuff with it.
Flipcode
I really only go to this site because of the portal stuff. I haven't found much that I couldn't find in the above sites aside from that.
GNU GCC
DJGPP is a free, DOS/Windows compatible command-line compiler. Doesn't work in Windows XP yet though, so be warned.
Allegro.cc
The Allegro community base. Check it out, lots of stuff here.
Pixia
Pretty good free Image Manipulation program.
HyperCam
Screen capture program. Good for making AVIs of your game in action. Its not free, but everything that matters is in the demo and it doesn't run out.
IconArchive
This is a great site for some icons for your programs - there is even an icon ripper utility here; very useful.
PvP Online
Another cool comic strip, updated daily.
Homestar Runner
Homestar Runner! What you're really looking for is StrongBad stuff. Its all about StrongBad! To the limit!
MegaTokyo
A cool manga made by some american guy. Strangely, it has little american influence. Still a good read.
Real Life Comics
Another webcomic, this one's daily, I think. I haven't been hitting it very often lately.
Nintendo metal
Music band that does original metal using Nintendo game songs. I got their demo cd - pretty friggin cool. I'm hooked on Cataclysmic Clash. Download Little Mac's Confession and judge for yourself - very high quality music.