Butch Hartman (Fairly Oddparents, Danny Phantom, T.U.F.F. Puppy)
I love Butch Hartman's cartoons. His sense of humor is very reminiscent of Chuck Jones, and his art style is very unique.
Genndy Tartakovsky (Dexter's Lab, Samurai Jack)
He is brilliant. Samurai Jack was the best cartoon ever made, with an incredibly unique art style and amazing animation. It's a shame he hasn't been doing much lately. Was Hotel Transylvania any good? EDIT: Hotel Transylvania was amazing. I never thought of Sony Pictures Animation as a respectable studio (all because of that wreck that was Open Season), but they did a great job with this movie. Are they the next DreamWorks?
Craig McCracken (Powerpuff Girls, Foster's Home For Imaginary Friends)
He made a show about butt-kicking girls cool. And Foster's is a very weird and funny cartoon.
John Kricfalusci (Ren & Stimpy, George Liquor)
He is a very outspoken critic of modern cartoons, and a collector of classic animation memorabilia. He was one of the first cartoonists to extensively use Flash, and he makes webtoons occasionally. His sense of humor borders on the bizarre, almost like an extreme version of Tex Avery, but his art style and sense of comic timing is unmatched.