I use atomhost.
It can be a little difficult to setup the forums but they give you really good instructions with the forums. These are PHPBB. I like them because there are lots of mods...also I have figured out a way to block the bots that make accounts and post porn. vbullitan, ikonboard, and phpbb are all good canned boards to go with. Just remember to follow the insturctions to the letter if you have not done an install before or are not familiar with SQL, basic unix and perl scripts.
I am happy to help if you need it. Maybe we could arrange some plugs for the boards eh? *wink*
PS atomhost has some neat features...like you can push a button and it automagically setsup/installs all sorts of stuff like galleries, blogs, and forums....not PHPBB but they have some automagic forums....I think