I really like Matta's work. He was a Chilean surrealist and when I was an undergrad, I worked in a museum that had his piece
Je m'arche on permanent display. I don't know why, but I really liked it from day one. He was an more abstract surrealist than Dali or Matisse, but he still had defined images and figures in his works. He was obsessed with Jung's "collective unconscious," so he was attempting to relay collective and essential human feelings and experiences while also analyzing things like the interaction between the mechanic and organic.
Je m'archehttp://www.matta-art.com/popup.htm?jemarche.jpgHere's a site with a lot of his art:
http://www.matta-art.com/ .
I'm not the biggest fan of the extreme abstract expressionism work in Rothko's late period, I respect his philosophy behind them. I prefer his earlier works, but I probably wouldn't call him a favorite.
And I actually really like Don Pendleton's work, both within and outside of skating. My parents bought me an original painting of his for my college graduation.
http://bull-in-an-abattoir.tumblr.com/image/6166508417