Understanding BuddyPress Forums vs bbPress


I know this is a basic question but I'm having trouble wrapping my mind on how best to set up forums in a Membership-based BuddyPress site.

Before I start my install, I'm trying to understand if:

1) Do I need to install bbPress if I want to implement forums?

2) How does the BuddyPress Forum module differ from bbPress (or can they work together)?

Since I won't be doing a MU install, does that change any of my considerations.