Try the egullet region section for some rome suggestions:

http://forums.egullet.org/index.php?showtopic=40490

I would say stay away from the Hard Rock and maybe see if you can get something in Trastevere, Testaccio or the Centro Storico that can hold a private function.

I don't think I've really ever had a bad meal in Rome. I wish I could say the same for Venice.

lala