I have a lazy web request for a Gmail Firefox plug-in I don't see on any list (or, even better, a Gmail feature!): One-click add-to-killfile. It's way too many steps to create a new filteror add someone to an existing filterwhen you can't unsubscribe from their crap. So you end up not doing it. So you keep seeing the crap.
It would be theoretically easy to just grab the address of the current message and add it to a filter that skips your inbox.