Someone I know just suggested this great site:
http://www.opensourcecms.com/
It lets you test out all the forums as they would be. So you dont have to install them all yourself

(Save me some time)
I want to use this site for having a forum, links, very few dl's , some basic discussion and news. (Sort of hard to explain waht i want)
After using opensourcecms, i tested them all out and e107,geeklog,ldu and phpnuke fit my needs and work well. So pretty much I will go by which one looks and feels the best and has good themes.