Here's my list...
1.) Better looking templates. I love, love, love UBB threads. But it's ugly. I would get graphic designers with CSS knowledge involved to make it prettier. I would love a look akin to Facebook's design. I applaud the tableless design effort.
2.) A tool to archive members. I want to prune down my dead users who haven't posted but keep them available in the database so they're not really gone. This way I can research their data down the line if I need to but keep my database fresh.
3.) Chat functionality similar to Facebook's chat.
4.) Integration with Facebook/Twitter type APIs.
