Best forum software to use

I need to add a forum to the site so users and ask questions, get answers, etc. I have buddypress installed and was going to use that but it appears the user has to be part of a group before they can create a forum post. I would like to make it as easy as possible to post a forum question.

What would you suggest for good forum software that would allow users to post questions, with content like even photos or videos. The Q&A plugin looks nice (is this what you are using for your help tool I am typing on?) or would you suggest bbpress or just using the Buddypress forum tool?