Best Art: Razia's Purification
When you've got a card that goes *BOOM*, the art for the card should mirror that effect. This art is wonderful and it really sets the tone for the entire card. I also really like the fact that the yellows and reds in the art really blend well with the gold background of the card, giving it a seemingly full-art feel to the entire thing.
Worst Art: Dovescape
Now, this category was a real toss-up. Quash and Unblinking Bleb were strong contenders for this title, but I think this card is really the worst of Shishizaru's art. The art is still good, but I have no idea what's going on here. At first I thought it was a charm-like card (see Esper Charm for an example) with the charm firing a laser out of the center but I don't think that's what's being represented.
Most "Huh?" Art; Unblinking Bleb
It didn't win the "worst art" contest, but it definitely wins this one. Just like Dovescape, I have very little idea what's going on here, but at least with Dovescape, you can at least guess what's going on in that picture. With this art, I can't even tell where the creature is (although I think the giant eye may be a clue).
It's sad Shishizaru didn't do much art in Magic, but I guess he's busy doing other stuff. Feel free to visit his website here (be warned, it's in Japanese).