Joomla is one of the best open source online Content Management Systems (CMS). the latest version is Joomla! 1.0.12 [ Sunfire ], which was released in Dec. last year.
One major criticism is that all Joomla! sites look alike. You can't do much about the "Joomla look" but there are several templates out there on the net, both free and commercial, that you can personalise to your taste.
Found a nice list of different Joomla template sites on the o! Just Me blog.