I use to use Blogger for a little while but I didn't like how you couldn't tottally customize it as much as I would have wanted it to. The nice thing about it is that its simple to setup and use. No webhost needed since its all handled by google.
Joomla is full blown CMS (Content Management System) and is great for making a full blown site data driven site, but is way too big if you're gonna just make a blog.
Plus I found it a bit way too non-userfriendly, and it isn't really meant for blogging. There are plugins you can find that will allow you to set up blogs though but I never tried them.
Wordpress is definately the route to go. Its freely available and very easy to use and setup. Tons of free plugins and themes everywhere. And since its open source you can customize and hack the hell out of it. Matter of fact, you can even set it up to be a CMS site if need be. The catch is that you'll need a webhost setup first. But i definately prefer it that way anyways. I'm currently using it for my little blog on the Wii :
The Wii Effect.