I know some people will say it depends on what you want blah blah blah I'm not here to talk about that. I'm here to talk about who is the champion. Who can stay in the ring and claim to be the winner.
Drupal Rules!! Indeed Drupal is a CMS, but its a powerful blogging platform too. check my blog to it in action
what?...you can't say which is the champion unless you determine what they are going to be the champion of... that's like asking who's the champion out of Tiger Woods, Dale Jr, Bill Clinton, and Donald Trump
u can't really compare these 4. Joomla and Drupal => CMS that can also function as Blogs Worpress and Blogger => Blogs with the exception of WP which can be a very simple CMS. If you must compare I'd vote for joomla cause of how simple it is to either get a full blown site using it as a proper CMS or having another blog based on joomla. either way joomla can blog and function as cms
I was a huge proponent for Joomla for years, but since trying Wordpress, it has blown me away. Wordpress FTW.