Who's the music artist that you've liked for the longest?Watch
I was a massive fan of them twenty years ago.
If by "music artist" you mean someone who writes/wrote music, I'd probably say Mozart, I was listening to his work right from being a baby.
If you mean singer/band, probably Pink Floyd.
As for individual artists, I do try to keep an eye on what Tosin Abasi does, one of the best guitarists around today and always seems to come up with fun, interesting pieces of music.
If we're talking genre, it's Hindi and Punjabi music. Been listening to both since childhood and I consider them part of my upbringing.