Surreal Game Design is a group blog on game design by the designers - all 17 of them! - at Surreal Software in Seattle. They make me feel inadequate by writing lots of great articles about professional game design, but then again, they're 17 and I am just by myself. Also, I need a lot of time to trawl the web for funny cat pictures and stuff.
Anyway, go check them out if you want to read about game design from people in the trenches. And if you like what you're reading, you can see if they have open vacancies on the same site! Smart.