TextPattern, Nucleus, b2evolution and Movable Type.
http://www.movabletype.org/
ExpressionEngine
http://www.expressionengine.com/
http://www.softaculous.com/softwares/blogs
b2evolution only a 200+ plugins (compared to Joomla’s 3,400+).
http://b2evolution.net/
Nucleus CMS
Nucleus has a much more active release schedule than b2
http://www.nucleuscms.org/
Serendipity
Serendipity doesn’t offer a multiple blogs with just one installation
http://www.s9y.org/
10 Weblog Engines Reviewed
http://www.smashingmagazine.com/2008/08/29/10-weblog-engines-reviewed/
http://www.cmsmatrix.com/
Expression Engine vs Textpattern
http://www.hicksdesign.co.uk/journal/expression-engine-vs-textpattern
Dotclear
http://dotclear.org/