I have a couple suggestions

MatthewAlan

I think there should be some kind of mark all forums read button it's not a big deal either way.

Also, I think there should be a place where you can see what discussions a user is involved in, not just ones they have started. Also along those lines, maybe something to see how many posts a user has.

SubJunk

There is an extension for Vanilla 1 called something like "mark all read"