Scott Aaronson's blog is so awesome. I would be reading it now if I still had room in my head for the whole 'rationalist' thing (along with Overcoming Bias, etc.) Check out his "Favorite Posts" in the right-hand column.
Lambda the Ultimate is also a rare gem of a community on the internet and likewise I'd still be reading it if I wasn't trying to care less about design and more about hustle right now. I'm really interested in dataflow programming and I've learned a lot by searching through previous discussions on the concept at LtU.
http://nosql.mypopescu.com/
http://lambda-the-ultimate.org/
http://eli.thegreenplace.net/
http://www.stefankrause.net/wp/
http://mechanical-sympathy.blogspot.com/
http://www.cowtowncoder.com/blog/blog.html
http://highlyscalable.wordpress.com/
http://hunch.net/
http://perspectives.mvdirona.com/
http://www.scottaaronson.com/blog/
http://www.softwarebyrob.com/
http://blog.mikemccandless.com/