Hi Steve,
Welcome back (again) ;)
Q4 owners don't appear to be the chattiest of people these days!
For me, just a simple, functional forum where there is some discussion with easy photo uploads.
I don't need or use the garage feature (currently car of the week is Mini Cooper!), or the news feed at the top. The bookmarks under your post for FB, Digg, Twitter etc can go too.
The biggest problem is the registration process and spamming.
I think after spending so much time moderating and deleting spam users I put the registration of new users is currently on an Admin authorisation basis.
I am sure this can be remedied with a software update and introduce the Google reCaptcha feature.
https://www.google.com/recaptcha/intro/