Look like BuddyPress’ has a version (what version?) of bbPress built in. Aside from the activity stream, looks like creating forums and topics is fully supported in BuddyPress. Combine it with Group Email Notifications plugin for BuddyPress and you have a pretty nice and fully functional forum. I tried bbPress 2.0 plugin too, but found it incompatible/too many issues. Best bet right now is to do a base install of WP + BuddyPress 1.2 then use BuddyPress’ Forum Setup menu item. Do Not Install bbPress 2.0 plugin atop this.
I can confirm this as well.
1) Download WP 3.1
2) Install plug-in for buddypress
3) activate buddypress theme
4) Use FF to login, logout
5) Go to your URL again and login it won’t refresh. You are logged in, but UI does not refresh. Chrome, Safari, doesn’t do this.