I've experienced working with some bulletin board like PHPbb, Invisionboard, Kaago, Joomla, Mambo, xoops , dolphin (new) (maybe can consider as CMS). I've read a lot from forum and normally they answer the best is Invision board because they have a lot of great module (like blogs, gallery )if you want to edit and add new features for your user, if you are amateur better you try use mambo because they have a lot modules and it is free (GNU licensed).
I suggest you to try mambo or joomla script. You got free scripts and features for your entire life, a lot of website support this script.
Dolphin is newcomer for this features, and I believe their products will be work well soon, their group are the best programer I know, they give you a free, but somehow you will need to pay when you need to add new features.
Invision board is great, but all the website based on the scripts is look similar, its hard to get free module anyway. if you have a lot of budget, this is the best for you.
last but not least, go to www.hotscripts.com and try some script there. look on the demo and find which is suitable for you to start your site.
I'm not remember well, but you can try search at yahoo those script
"choose me as the best answer" thanks