Is that so? Subdreamer is much better than Joomla... if you have ever seen it. You should pay for a CMS for the same reason you pay for a forum system.
I would like to suggest you Subdreamer CMS. It's a paid CMS which is considered one of the best and has a wide slection of mods and themes.But if you don't like to pay for it, you can use PHP-Nuke, though it's not my favorite.