I'm partial to Wordpress.
wordpress.org
Pros: They will host your blog and take care of enhancements and upgrades. You show up in people's related blog listings and searches.
Cons: There are limits to customization. Additional services such as redirects to custom domain names require the purchase of credits.
wordpress.com
If you're a bit more technically saavy, you can download the free Wordpress client and install it on your own server. No compiler necessary --the install procedure is actually quite simple.
Pros: You have more flexibility with customization.
Cons: You have to upgrade your own client. Because php is a base component of the Wordpress client, security patches are released frequently.
I also seem to recall reading somewhere that the wordpress team would be happy to install wordpress for you.
Hope this helps!
Alex.