I've actually thought about that question a lot, for some reason...
I think most of all, I'd hate to go deaf- which surprises some people, as I'm generally known as one of those arty-types, therefore I'd be expected to go insane if I couldn't see something right? Wrong. I mean, ok, it'd suck some huge ass not being able to see anything again, but imagine never being able to listen to your favourite song, or eavesdrop on conversations, or delight in the squeal of burning rubber...
Of course, next to that, I don't think I could even begin to comprehend what it would be like to never be able to speak...
Dugtrio used Earthquake. It's super effective.