Wordpress is dead simple, flexible, and offers an infinite array of plugins (Of particular value are Akismet for spam filtering and some of the Cache plugins that make your pages serve fast).
On the down side, it requires constant security updates, and has a bit of a learning curve if you're trying to customize it. (It's also in written in PHP, which is a big problem for some people).
I've used it on my personal site and many work projects and found it to be great as long as you're willing to pay attention to updates and find/install plugins that fit your site.
