When I read the thread title, these two names are the ones that sprang to my mind as well.
Stephen King. He has been the creative mind behind several of the best films of the last few decades like the green mile, shawshank redemption and stand by me. Many other films based on his work are also very high quality (misery, creepshow, shining, etc)
As far as comedy, Doug Stanhope.
No idea for music.
Although I’m in no place to judge, I’d put forward Damon Albarn as a candidate.
Alan Moore and Neil Gaiman both deserve to be called geniuses as well.
Fabrice Bellard is a standout genius programmer in a field where merely having a high IQ isn’t that special. I can explain why he’s so amazing if anyone cares; for me, his work speaks for itself, but it’s a bit opaque to someone coming in completely cold.
Donald Knuth, of course, is a demigod, but the fact he merged his amazing programming skills with strong writing and teaching skills and a not-inconsiderable artistic ability is worthy of special note.
Software is art if architecture is art, and if you don’t see architecture as art, you’re blind.
Radiohead
Trey Parker
I’ll second Neil Gaiman and add Ani DiFranco.
Neil Gaiman is the most consistent prolific fiction writer working today that I know of. Garry Wills is the most consistent prolific nonfiction writer working today that I know of. I can’t include Tom Lehrer, I guess, since he’s no longer active, but he’s the best satirical singer/songwriter of the past century that I know of.