I really love Futurama, but the new seasons (this latest one in particular) have been god awful - the jokes are so stiff, cheesy, and utterly predictable that its kinda hard to believe its the same show.
Adventure Time is probably the best thing going right now on Cartoon Network, Regular Show also deserves a mention. The Marvelous Misadventures of Flapjack is another great CT show that got cancelled way too soon.
Cartoons probably my favorite thing on television - it's just so much easier to be creative in an animated format than one that's filmed. It's one of the few genres where imagination and outside-of-the-box thinking is actually rewarded.