Samurai Jack's still pretty sweet, but CN has got some good stuff going on. I'm in love with Adventure Time and Regular Show, and what I've seen of MAD TV and the new Thundercats is great. I wish I could've caught Symbionic Titan when it was still on the air, but sadly it doesn't look as though it's going to get renewed. At least there's the Samurai Jack movie to look forward to.
I haven't seen the new Thundercats, but MAD TV sucks. The only good thing they have is Spy v. Spy.
It's like, it tries to be Robot Chicken 4 kiddiez, and it fails spectacularly. Mostly because the only reason Robot Chicken is funny is because of how far it goes. Mad can't do that, because it airs in the daytime. Even so though, it could be better. The humor now is mostly "Hahaha this celebrity iz so dum haha look." It's not so much parody as it is the bullcrap that little 8 year olds think would be funny.
Then again, that's probably their demographic.