[laurenproctor]

I second the recommendations for Wordpress, but only if you're committed to maintaining your own domain. If you don't mind spending a little bit of money on hosting, the platform is simple, flexible, and pretty powerful. Plus, you'll have total control.

If you want to farm out to someone else, tumblr is good because it's inherently social (people will follow you, share your posts, etc), but it's largely visual and a bit spammy at times.

Posterous is another good platform because it's simple, has some social features, and tends toward the more content driven format.

Wordpress is still my vote though, because it can grow with your blog/site and vary from the fairly simple to as advanced as you want.