I can't quite believe this thread - maybe people should look up the words 'original' and genius in a dictionary because a lot of the names mentioned in this thread so far fall way short of both of those definitions. Don't get me wrong, I'm not saying they are bad, I'm not saying they don't approach their music from unusual angles etc. but please, if we are talking about genius then we are talking about the sort of gifts that come along maybe half a dozen times in each generation, across all disciplines of human activity, not dozen upon dozen in the realm of pop music.
If you really look at the history or rock and pop (say from 1920 up to today) I think you would be hard pressed to find more than ten people who really, genuinely live up to the title of genius, and maybe fifty to a hundred who were truly original.