Re: subforums and markup
Sooner or later you may want these other tweaks too:
http://ckon.wordpress.com/2007/07/12/bbpress-plugin-bb-tweaks/
1. Get rid of the ?replies=# ugliness in topic links
2. add nofollow to post links
3. add target=_blank to post links
4. auto-close tags – bbPress’s auto-close tags is broken by default
5. get rid of [closed] on subjects – useful if you have a narrow template