I use b2 from cafelog.com, I find that it is the easiest to install and fastest blogger. I also use w.blogger to update it and it makes posting that much faster. I also like b2 more than movable type because b2 is completely written in PHP and uses MySQL for the more security, if you haven’t already started using movable type I would suggest b2 instead
Oh yeah and did I mention it's free (Open Source)