I will play a devil's advocate here and say Wordpress is the best.
I have only limited experience with Joomla and others, though, so I cannot really compare them. But I have been using Wordpress for years now and I must say I have never had any problem with it. It's core is clean and semantic and it offers almost limitless options for customization - you just need to know PHP a bit. Moreover, there are hundreds of useful plugins that expand basic Wordpress' functionality (which is, imo, impressive, offers all you need) plus it is pretty easy to create your own plugins.
I have taken a quick look at Joomla few months ago and while it might have some more functions right out of the box, I must say it is much more confusing and not very clean or semantic. Code isn't as clean as in Wordpress and there are some compatibility issues, as far as I know.
There is also a forum software created by Wordpress developers that goes hand in hadn with Wordpress CMS -
http://bbpress.org/
norbx said:
does anyone know of any good custom cms? or very good paid cms's?
If you want a top-notch quality and support, I suggest
Graffiti CMS. It is pretty expensive, though.