Depends on your definition of "rude," honestly. If speeding and not signaling fit that definition, then a lot of east coast states will be on the list.
On the other hand, if
Other drivers suck everywhere. Get off my road! (or at least try passing when you're in the passing lane)
applies, then drivers on the west coast, particularly the Pacific Northwest will be high on that list.
I'd have a top 5 worst of California, Oregon, Washington, Florida and Texas, but I haven't driven on the East coast at all. Michigan, for what it's worth, is the state with the least bad drivers in my experience.