It would be nice if we had the ability to block a user from sending us any PM's.
It might even be cool to be able to block the comments of any one that you choose from the threads - there is always one or two guys that for what ever reason seem to bring negativity to any discussion without ever contributing and they really don't care. They even get their rock off by doing it. So, asking them to stop just feeds the fire. There are several ways to do this on Facebook, surely we should be able find a way to do that here.