I also think that RS232, etc are better. I also think that it is better to have separate cables for audio/video (I would use one way digital video (with encryption or other complications) and balanced analog audio; can a variant RCA connector be made which is capable of balanced signal while also compatible either way with non-balanced too?), and to have separate ports for different purposes and numbers that they are addressable by, which is more secure and also to be able to address them by software in the computer by which port they are connected to. (I think USB is bad in many other ways too, though.)
