Seems the new kid on the blogware/cms block is Habari. It's still early days yet, but keep any eye on this one. If you're on a Mac, you can install MAMP and give it a try on your localhost. Contribute at #habari on irc.freenode.net.
13th January
Habari is spreading
Write a weblog for the BBC Radio 4 Today programme during the UK elections.