I really like Ryan Ottley's stuff. It has enough detail to look great but not take Todd Mcfarlane levels of time. (For the record, I think Todd Mcfarlane IS a great artist.)
I also like the grittier, more uses-a-lot-of-blacksier Jim Lee art in All Star Batman and Robin.
I like pretty much anything in terms of Street Fighter art. Not only is the official stuff fun to look at but it even inspires really great fan art.
I really like the art in Avatar. If I had a cartoon I would want it to be similar in style to this.
Similarly to Street Fighter, I like just about all of the Legend of Zelda art too, and it inspires some pretty epic fan works.
I used to like Ultimate Spider-Man a lot. The first 100 or so, before the artist swap...
Anyone familiar with Calvin and Hobbes knows there's a number of reasons to love it, but I'll go with the expressions. Great expressions.
I like Soul Eater's art. Yeah, there's about 1002 manga/anime with almost the same "style" but what can I say?
Also a fan of Jhonen Vasquez. He has a fun and simple art style, plus his sense of humor is pretty close to mine.