Phineas and Ferb is love.
It's just. So hilarious. xD And they can make a song out of just about anything.
I'd also agree with Jemi on Firefly and the Big Bang Theory. Firefly 'cause, hey. Space-Westerns are just awesome.
And Big Bang has both an awesome intro and humor that just pegs it perfectly.
Although, I do feel weird laughing at some of the dirtier jokes around my dad. x3
Ahm. House, of course. Don't think I even have to explain this one. xD
And Avatar. I swear, it's the best, most thought-out cartoon I can even think of. Everything came back and had some significance at some point.
That's what made the ending so freaking amazing.
It's hilarious along the way, too, hah.
If anime counts, omg Trigunnn. ♥ It was pretty much the first anime I really grew to love. I'd seen a couple anime before it, but Trigun just took the cake for me.
Mostly with a nice balance of humor (and I swear, Mister Nightow's sense of humor is pure amazing xD) and story, kinda like Avatar has.
Now if only they'd hurry up and dub that movie. >:U
And I haven't quite finished it yet, but Hellsing's pretty good too. Just wish it didn't have so darn little explanation for things. o_o I pretty much went through the TV series feeling completely confused.
So far the OVA's been much better about explaining stuff and actually wrapping situations up though, so.