I love M. C. Escher a whole bunch. I love his metamorphosis works, and his playing around with impossible shapes and structures. Most of his works are just plain fun to look at, besides.
"Other World"
"Relativity"
"Metamorphosis II"
"Belvedere"
"Concentric Rinds"
Rocket, duh.
Anthony Frederick Sandys is pretty kickass. He's the only artist where I've liked every piece I've ever seen by him. Oh, and I like most of Gustav Klimts work.
I'm going to be very brave and very stupid and say that these 2 deviantart artists are awesome to the nth degree. They're certainly not Van Gogh, but still I'm really interested to see what they do in the future.