I feel sadder than I expected, somehow. Apart from the hits, I never really knew his music (I rarely buy music) but his hits were superb and hugely idiosyncratic. The riff from "Man Who Sold The World" is the greatest two-note signature in music - ahead of Teen Spirit and Beethoven's Fifth, which is also not bad.
A real quirk. Rest in Peace.
PS I'm full of admiration for the way his illness seems to have been kept secret, so that his death has taken the media vultures completely by surprise. I'd have expected nothing else, really, he really was a smooth operator.