What is the best theme for forums?

Hi,

I wish to create a content reach website. I have a very big community in facebook, so I need a theme / plugin that will allow me to use many forums, with social capabilities. I would like, also to keep all of the content abilities and to use several sub domains all with the same login details.

While I understand I probably need both MU and Buudypress, I wonder if there is a good theme that could save me time in modification and that supports forums.

Please advise,

Ofer