I found an interesting site today called NITLE Weblog Census I came upon this because the site was crawling my blogs and I did not recognize the name. They have some nice information about the proliferation of blogs on the internet and go through and categorize quite a bit of information. The most pertinent information from that blog was the Blogging Tools MarketShare page. It shows that Movable Type is by far the most used stnadalone blogging tool out there, followed by b2 and by php-Nuke Some other interesting peices of information on that site as well. A good look-see.
i’ve used php-Nuke, but i did not care for the admin panel. never used b2 though.