Nirth: Something that has these things:
-advanced search
-more sub-forums
-ignore list (with wild cards, not just user based)
-a "do not display" for every fluffy option people might use like emoticons or signatures
-Ability to hide reputation points (this is to stop unnecessary flame wars about it)
Personal nitpick: the ability to lock people's avatar in place. I've never seen this before and it's not a big deal but it would be useful.
I haven't seen rep flame wars as much as I have a certain scammer just abusing it, and proudly admitting to it. Such as what he does to TinyE and myself.