I came to nominate Courageous Cat, but I see that someone else also had the discerning ear and good taste to do so. 
I also have to second George of the Jungle, Magilla Gorilla, Speed Racer, Tobor, and to cheat a little… the Looney Toons song.
By the way, was the* Courageous Cat *theme the same as the one for Peter Gunn?
Animaniacs is my vote.
Key: The Metal Idol is pretty good.
Nazca rules though.
As does Kacho Ohji
And Lain
Tank! (Cowboy BeBop) is so far ahead of everything else that there’s really no contest.
However, I do like The Animaniacs theme.
Samurai Champloo
The Boondocks
Animaniacs
Teenaged Mutant Ninja Turtles is good.
I also remember likeing the song to Disney’s Tailspin.
As far as theme songs with no lyrics, two of my favorites are Exo Squad and Roughnecks: The Starship Trooper Chronicles
Most of my lyric’d favorites have already been picked, based on the quick browse-through I gave the thread, but I’d like to throw in a special vote for the movie version of the GI Joe theme song, complete with Cobra’s theme song.
True. At best, this thread is a battle for second place.
Pinky and the Brain, I Am Weasel, The Mysterious Cities of Gold, Scooby Doo, The Littles, Little Lulu, The Pink Panther, Inspector Gadget, and Dangermouse all were great.
I know the movie theme was used as incidental music on the TV show, but unless you’re talking about a different show, this was the theme the Pink Panther Show.
What? No mention of Cecil the Seasick Sea Serpent? If nothing else, they get bonus points for the line “your obedient serpent”, not to mention “A Bob Clam-pett Car-tooooo-oooooon!”
Ask my daughter about it, she loves it.
Damn but I loved that show as a kid. Still do 
Anyone outside of the UK heard the theme to Bananaman? Catchy, but the voice over makes it;
“This is 29, Acacia Road. And this is Eric, the schoolboy who leads an exciting double life. For when Eric eats a banana, an amazing transformation occurs. Eric is Bananaman. Ever alert for the call to action.”
Reminds me too, I bought Bagpuss on DVD, that has a rather touching theme tune with voice over too.
No one has mentioned Beany and Cecil???
Come on kids let’s flip our lids
Higher than the moon
It’s our obedient serpent in
a Bob Clampett cartoo-ooon.
And yes, that was from memory.
An honorable mention surely must go to the theme from Teen Titans.
Both versions!
I’m 46 years old I will find myself humming it.
There were three versions. The episode with a Robin from another dimension, Nosyarg Kcid, had a hilarious opening with the Japanese version of the theme being sung by a drunken-sounding man.
Damn, I want to see that!
Chip-chip-chip-chip chip and Dale, Rescue Rangers. Chip-chip-chip-chip and Dale, when there’s danger!
Also, the ending theme to Avatar has some good Taiko drumming.
“George of the Jungle” gets my vote.
Forgive my reviving a long-dead zombie, but I just found Pizzabrat’s complaint, and I just have to make things right.
The linked site used the wrong theme, which actually goes to the theme from the Fleischer Superman cartoons from the '40s.
What I was referring to was the Filmation series, “The New Adventures Of Superman”, of which the theme and an episode can be seen here:
Pizzabrat, if you happen to drop by, I hope you’ve stopped hating me by now.
How about the theme from Dilbert?