Rationalist Blogs you positively must visit dah-ling.
No one has asked my advice on what blogs ought to catch their fancy, or that they ought to chance. I am, however going to give my opinion to you like it or not!
Anyone interested in the neat facts about evolutionary biology, or the dogged fight taking place in this country (US) and increasing in the UK really ought to read Jerry Coyne's blog, Why Evolution is True. Coyne recently wrote what many are considering one of the best books of the year on evolution (also called, Why Evolution is True and is a Professor at the University of Chicago, in their Evolution and Ecoloy Department. Excellent writer, broad scope of knowledge. You cannot go wrong.
Another vigorous defender of the sciences is P.Z. Myers, prolific blogger, and professor at the University of Wisconsin Madison. He caused frothing at the mouth last summer over his "Its just a fackin cracker" comment while also offering to descrate a communion wafer (the cracker in quesiton) to prove that, in fact, crackers could not be injured or offended despite the claims of professional offense-takers like Bill Donehue of the Catholic League. Myers current critique of Simon Conway-Morris, co-discoverer of the Burgess Shale fauna is a wonderful read.
Another wonderful blog to get aquainted is Skepchick. Several women and one deserving guy doing their bit to defend rationality. They are a funny bunch. Check them out. You won't be disappointed.