The forums aren't that bad, but I find the template resembles the default one a bit too much. What really needs jazzing up is the forum names and descriptions. Instead of "Operating Systems - Argue about the latest OSes," why not use something more creative, like "Hello, I'm a Mac, and I'm a PC - Discuss the latest operating systems that power your computer or machine."
That's just an example. I don't like my own name for that, but you get the idea. phpBB SEO wouldn't be a bad idea either, if you can get it to run.
Good luck, though.
Oh, forgot to mention. Don't use Absolution (for the reason that everyone uses it these days), but you can take a look at how a theme like that one resembles the default less.