Hey guys, I run a vBulletin board as well, and you actually can exclude a forum from the New Posts search. P&N is forum #24 here, so just append "&exclude=24" to the end of the search URL, and it'll skip posts from that forum. You could bookmark this and use it in place of the New Posts button:
We have the exact same issue on our forum -- a politics area that a lot of people don't want anything to do with -- so that's a big help for them.
Hope that helps!