Weird, I've seen Gumball a handful of times, and recognize the theme music, but I've never seen that opening sequence. Maybe it's because I usually just have the TV on in the background without watching too closely.>>873
There's a handful of shows on Cartoon Network that I think are pretty good.
Adventure Time, obviously
Regular Show feels like it was written by/for people who grew up in the 80s and 90s.
Gumball is pretty good.
We Bare Bears is also pretty cute.