Though I'm not as guilty of chronically changing content management/blogging software as I am of switching up Linux distributions, I've used more than a few in my day. I began using WordPress in its 1.x days, and moved through Drupal, Mambo, and Joomla in a quest to see what really worked best for my situation.
A year and a half ago, I ended up returning to -- and staying with -- WordPress. The software was nicely polished, simple to modify and configure on a superficial level (and slightly more complex but not frustratingly so for deeper changes), and third party plugins were available that were useful and worked flawlessly (or at least, without show stopping errors).
The WordPress 2.5 release introduced a very different layout and new features, and the 2.7 beta shows the team shaking it up again. In this release, WordPress is lending a hand to (lazy? Overbooked?) bloggers everywhere.
