I have always been a major Wordpress fan and used any opportunity to plug both Wordpress.com and Wordpress.org. Now - I have an even greater reason to speak their praises: Wordpress 2.7 is exceptional. I have been using the latest version at Widgetbox's blog for a few weeks - and just recently upgraded this blog to Wordpress 2.7.1.
Mind you I have used countless different versions up to this point - all of which were more evolutionary than profoundly new or different. With the latest version - that changes. For instance, moving from Wordpress 2.3 to 2.7 is almost entirely a new experience (from the interface to the feature-set to the available plugins and so forth).
What strikes me about Wordpress is what also what strikes me about eBay, Google and other web giants:
They have enabled millions of users to create content and create businesses / economies around it. From professional bloggers to (more interestingly....) developers and designers (plugins, themes, etc) - there is an entire economy based off the popularity and flexibility of Wordpress. This was one of the most satisfying parts of working at eBay - enabling millions of people to create value through the platfrom - either directly or tangentially.