PHP Fusion - Nice CMS, I'm using this one for 2 sites right now. Easy customize and there's lots of themes & add-ons for it. The panel system is a nice feature, allowing you to easily place bits of code across multiple pages, for example and affiliates or advertising box. Comes with basic forums. Forum and support and quick to respond and are very helpful. Very user friendly.
Joomla! - I used this before though it's been a while since I used it, about a year or 2 I think. Judging from what they had when I was using it there's a lot more add-ons and themes available for Fusion. It kind of depends on what you're looking in a CMS.