I don't know if you've been reading the Bad Astronomy Blog or not, but if not, you might at least take a look. His web site is very fun, and his blog is written with the right combination of humor and hard science to make it hit the spot for a semi-daily read.
Plus, you can tell the guy loved Teenage Mutant Ninja Turtles. I mean, what else can make you say "Oh, barf. Unknown forces. Puh-leeze."
Edit: Evidently, it's "blog day". Here's four more links you may not be aware of:
New World Life keeps tabs on SecondLife. It's the most reliable and interesting SecondLife blog I'm aware of.
The Freakonomics Blog is probably the most readable economics blog in the universe. It's the only one I'll suggest for general consumption, at least. It's extremely interesting.
Seth Godin's Blog is a marketing blog. Marketing has more readable blogs than economics, but Seth's blog still stacks well.
The Artful Writer is one of the half-dozen writer's blogs on my list. I won't say he's my favorite, but he's very, very good.
I also have a few cog sci blogs, but they're heavy-ass reading, so I won't go spouting them. You can always hit up my bloglines account for a more complete list of the 83 blogs on my feed. That's not as bad as it sounds: most of them only post once a week or so, and some of them are totally dormant.