I agree with CarolC ...Frank Zappa is the first name that pops into my mind when I think of recent musical geniuses...

But he's dead. So is John Lennon, whose name comes second to mind. He revolutionized pop music.

When I try to think of someone alive today, it's a little harder. Jim White, maybe. At the least he's the best living American songwriter that I've heard (my opinion, of course).

Historically and classicaslly speaking, Chopin and Mozart. The stuff they wrote way back when must've sounded revolutionary to audiences then, because certain passages sound amazingly contemporary to me now.

More recently in the classical vein, Charles Ives and Schoenberg. The ideas of Ives' work were being formulated around the turn of the twentieth century. Then, they were lightyears ahead of their time. It took the rest of the world about fifty years to catch up. His fourth symphony is a masterpiece. Schoenberg's (I'll probably take some heat on Schoenberg - you either like atonal stuff or you don't) atonal ideas were genius.

Jazzically - Oscar Peterson and Bill Evans. The depth and breadth of musical ideas that flowed out of them were genius.

Probably lots of other musical geniuses that escape memory at the present ...