Much easier to say which ones I hate. I've thoroughly enjoyed Cartoon Network's originals with the exception of a handful. It's too easy to say the live action abominations, Annoying Orange, or Johnny Test. But yeah... I like most of the shows from Dexter's Lab to We Bare Bears and most of them inbetween. Can't exactly say which ones I'd consider favorites, as the shows are varied and offer different things.
All I can say is, the only (that I've seen) Cartoon Network original I openly hate is that thing about the animal school that a human goes to. Nothing about that show is original, clever, or well done. Even Tom Kenny feels overused in this show.