Those reality shows are the only thing that don't really fit on CN at all. I didn't really found Flapjack too funny except for a couple of episodes, Chowder was an excellent show with a good theme going on, but ended too soon, Adventure Time is REALLY good, and I love the Total Drama series as it really does get intense at certain parts, also a little disgusting which I don't mind. And their original action shows like Ben 10, Generator Rex, and Sim Bionic Titan are all great shows for Friday night/saturday morning.
I think Dexters Lab is airing now on CN at 12:00 on week days, and I know they still show K.N.D, Ed, Edd, & Eddy, Grim Adventures and Courage, but I really won't them to re-air Powerpuff Girls, Two stupid Dogs, Johhny Bravo and Samurai Jack.
As for Nick, they really should stop constantly showing Spongebob every freaking second and bring back some of their old toons like My Life as a Teenage Robot, Rocko's Modern Life, Danny Phantom, and Invader Zim.
I have nothing to comment on Disney Channel as I don't bother to watch it, but they could at least show some old school Mickey, Donald, and Goofy toons.
Saddly, I don't have Boomerang, Nicktoons, or Jetix/Disney XD