Hate to dig up an old thread, but I love discussing artwork.
Uptil about when prophecy came out. RKF (it is Richard Kane-Fergasun, right?) was probably my favourite artists, things like flame elemental and boomerang were outstanding. His art really matched the set.
Mark Zug caught my attention in Urza's Saga. I love Oil paints (I assume he uses them or my last statement is pretty stupid) and his blending was perfect, it was amazing work. Things like Serra angel are examples of his great work.
Kev Walker has seemed to be getting very popular, and I guess it just reflects what the magic community wants. His detail is very good, and it seems realistic. His art continues to amaze me.
Rebecca Guay is another of my favourite artists. Watercolours are always 'interesting', at least to me, and she does a great job with them. Does anyone else notice the thick black lines she's using to outline her drawings these days?
Mark Tedin is a fav of mine as well. I have lots of his old stuff, live Nivenyrral's Disk, which is cool. Back in 4th ed, his work was much simplistic compared to work he's done these days. Things like flying carpet were pretty simplistic, compared to Phyrexian Colosuss (US and 7th ed). He's a great artist.
Donato Gianacola deserves great mention, as he is an incredible artist. Look at his site, I was blown away. I can't say much more.
However, my fav has to be RK Post. His imagination is amazing and his art is superb, my favourite peice has to be unmask, its amazing all by itself. You usually have more to say about your favourite artist, but I don't. Actions speak louder than words, I urge you to go to his site, which is hosted by daydream graphics.