I know that there's a link for marking all posts as read when you're on the screen with all the forums, but I think that it'd be pretty nice to have such a link in the little bar with the Calendar, New Posts, Members List, etc. links as well.
Specifically, this would be nice when using the new posts function when you've read everything that you care to. I'd say that it should be part of the search results for new posts, but I'm afraid that'd require changing how all search results are displayed - something that's not necessarily welcome.
Just a thought . . . .