I like 37 signals blog ( http://www.37signals.com/svn/ ). They do promote themselves, but they also have a lot of good insights. Apart from that, I main read what is linked to from dzone.com, programming.reddit.com, or occasionally digg, although not a big fan of digg.
I actually don't read any of the above unless linked from another source - too much noise, not enough signal.
I read Programming Reddit, News.YC, and occasionally Startupping and LambdaTheUltimate. I try to keep up with some blogs of startup-type people - Dharmesh Shah, Joe Kraus, Raganwald, Paul Buchheit, Mark Fletcher, and Marc Andreesen and Wil Schroter look interesting based on their recently-linked news.YC articles.
Also, don't underestimate the importance of good old fashioned dead-tree books. I know it's fashionable to spend all day online now, but I still find I get lots more information out of published works than the Internet (the net is great for pointers to books, though). I read a lot of history, economics, corporate histories, some biographies, theoretical computer science, etc. Some selected titles off my reading history (my library's software keeps track of books I've checked out):
"Founders at Work" (Jessica Livingston), "The Rockefeller Billions" (Jules Abels), "Stocks for the Long Run" (Jeremy Siegel), "The Intelligent Investor" (Benjamin Graham), "When Genius Failed" (Roger Lowenstein), "One Up on Wall Street" (Peter Lynch), "Why Smart People Make Big Money Mistakes" (Gary Belsky and Thomas Gilovich), "The General Theory of Employment, Interest, and Money" (John Maynard Keynes), "The Google Story" (David A. Vise), "When the Astors Owned New York" (Justin Kaplan), "Art of the Start" and "Rules for Revolutionaries" (Guy Kawasaki), "Purple Cow" and "Big Red Fez" and "All Marketers are Liars" (Seth Godin), "Microsoft Secrets" (Michael Cusumano), "Damn Right: Behind the scenes with Charlie Munger" (Janet Lowe), "Crossing the Chasm" (Geoffrey Moore), "A Good Hard Kick in the Pants" (Rob Adams), "Innovation and Entrepreneurship" and "The Essential Drucker" (Peter Drucker), "Only the Paranoid Survive" (Andy Grove), "dot.bomb: My days and nights at an Internet goliath" (J. David Kuo), "Accidental Empires" (Robery X. Cringely), "The Microsoft Way" (Randall Stross), "High St@kes, No Prisoners" (Charles Ferguson), "The Making of Microsoft" (Daniel Ichbiah and Susan L. Knepper), "AlmostPerfect: How a bunch of regular guys built WordPerfect Corporation" (W.E. Pete Peterson), "Direct from Dell" (Michael Dell), "Inside Intel" (Tim Jackson), "The Innovator's Dilemma" and "The Innovator's Solution" (Clayton Christianson), "Good to Great" and "Built to Last" (Jim Collins), and "Insanely Great: The Life and Times of Macintosh" and "Hackers" by Steven Levy.
http://www.scottaaronson.com/blog/
http://weblog.fortnow.com/
http://glinden.blogspot.com/
http://community.livejournal.com/evan_tech/
I used to have a blog called CleverCS that you may have heard of.