Hmm. Its kind of a hard question to ask, because most of the cartoons, that I like their theme song too...I never really "liked" until I got older. Or I never watched them as a child (or possibly an adult either. >.>)

I'll just post some good child show theme songs. Because the actual question is fairly impossible to ask.

[youtube]https://www.youtube.com/watch?v=2IrI2_w0CqA[/youtube] (Watched as a child, but never really got into the show.)

[youtube]https://www.youtube.com/watch?v=9eOJsm9ubGk[/youtube] (Haaaaaate this show. Also didn't see much of it as a child.)

[youtube]https://www.youtube.com/watch?v=emfezqBlYhI[/youtube] (Never watched an episode of power rangers in my life, but they have some pretty good themes. :P)

[youtube]https://www.youtube.com/watch?v=IVmtUK_1jh4[/youtube] (Okay I take that back, there's one particular theme and show I liked as a kid and still do.)