The ones I definitely watch whenever I can:
Family Guy
Ren & Stimpy
The Ripping Friends
The Tick
Futurama
The Flimpsons (you know the episode…)
South Park
Batman: Beyond
Spiderman (Spiderman, Spiderman, does whatever a spider can. Can he fly? Well, no.)
*
God bless the cartoon network!
Johnny Bravo
Powerpuff Girls
Courage, The Cowardly Dog
Most Looney Toons and Merry Melodies, except for the early Bugs Bunny cartoons (he seems too much like the early Daffy Duck in those.)
Personally, I like the later Daffy more.
“I can’t help it! I’m a greedy slob! Its my hobby! Save me!”
In no particular order:
Simpsons
Futurama
King of the Hill
Looney Toons
Ren and Stimpy
South Park
The Tick
Freakazoid
Johnny Bravo
Courage the Cowardly Dog (anyone else think the latest season sucks?)
Spongebob Squarepants
Animaniacs
Duckman
I’m sure there are others that I can’t think of at the moment.
And I can’t believe that no one has mentioned…
Beavis and Butthead! (heh heh heh)
Hmmm, although I’m ashamed to admit that I still enjoy cartoons, I’ll bite anyway:
Batman: The Animated Series, especially the early episodes.
The Simpsons, of course.
Sailor Moon. Yeah, the dialogue is incredible lame, but I love the underlying storyline.
Arthur and Friends. One of the few good children’s cartoons.
Digimon, the first two seasons. Would be alomst perfect if it weren’t for the fact that half the show is spent watching the characters transform.
Darkwing Duck
Daffy Duck
Count Duckula
I likes ducks.
Well I’m a big fan of The Simpsons and Futurama.
I try to regularly watch:
Batman Beyond
Justice League
Jackie Chan Adventures
Samurai Jack
Dragonball Z (though I think I’m not gonna invest in watching one they finish up the Buu saga)
Other Good cartoons that I usually don’t get around to are:
Powerpuff Girls
Dexter’s Lab (only the older episodes)
Spongebob Squarepants
X-Men: Evolution
Batman: TAS
Dragonball
Grim & Evil
Sealab 2021
Home Movies
Harvey Birdman
Invader Zim
I’ve lost interest South Park and Pokemon, and for some reason I found Family Guy and The Tick to only be mildly amusing.
I wish they’d make more Batman Beyond or make that rumored live action movie.
And give me my fix of Eltingville. That show is pure genius.
I was watching Justice League, but stopped. I’ll probably pick it up again in the summer during rerun season.
I loved Invader Zim. A curse on Nickelodeon for deciding to stop making it. You’re still using Zim in your promos though, aren’t you, you bastards!
Looney Tunes, of course. Wacky Daffy is so much better. My favorite is the one where he’s the “moustache fiend.” That just sounds dirty.
Sealab 2021 and some Adult Swim anime are weekly favorites.
Jackie Chan Adventures
It’s one of the two shows I watch on a fairly regular basis. I like the artwork, the characters, and the storyline’s aren’t all that bad.
The Magic Schoolbus was excellent!
I even learned stuff from it!
its on now at 6 a.m.
We are not up then…
Most of my favs are no longer on the air
90’s Spidey
Freakazoid
Earthworm Jim
The Tick
80’s Transformers (Has anyone seen the new one? EEK. I think I spent an hour trying to explain to my 8 year old why MY TF’s was better than HIS. sigh I’m headed to the DVD store this weekend)
The world stops when the Simpsons comes on.
I usually miss Futurama & Family Guy (absent minded), but I love these shows as well.
Then the usuals - Batman Beyond (my fav super hero/action cartoon), PowerPuff Girls, Batman, Spongebob…
Caught an episode of Baby Blues & was pleasantly surprised. Thought it would be watered down comic strip fare (Garfield, anyone?) and found myself laughing all the way through.
Although it didn’t make my “top” list, it’s definitely second-tier–I watch it 'cause my son loves it.
My 5-yr old son who, by the way, loves Ed and can do a remarkably dead-on impersonation of him, to wit:
“Buttered Toast!”
“Ketchup!”
and my personal fave:
“Soft and cuddly like mashed potatoes!”
Home Movies, on Cartoon network is made by the same people as Dr. Katz and has a quite similar sense of humor. In fact it’s the funniest thing on cartoon network.
Since I’m here, I’ll admit to liking:
Samurai Jack
Justice League
Powerpuff Girls
Tenchi Muyo First two series
Cowboy Bebop
Spongebob Squarepants
… and of course any Loony Tunes made before the '60s.
Hey, another MCOG fan! Have you heard anything about the new series? Supposedly it was shelved in 2001 due to lack of financing.
no tv, but lots of cartoons on disk… a lot of my favs have been mentioned, but other nifty ones are:
Gatchaman
Escaflowne
Generator Gawl
Kenshin
Vampire Princess Miyu
Armored Trooper Votoms
hmm… sensing a trend here…
My husband and I are currently addicted to:
Dragonball Z
Dragonball
Samurai Jack
Justice League
Powerpuff Girls
Invader Zim (I already miss Grrrrr) 
Futurama
The Simpsons (although it’s been getting pretty lame lately)
I miss The Critic and the former Batman/Superman hour, which was replaced by Batman Beyond. BBeyond got lame when every show seemed to be an allegory about kids doing drugs.
My husband and I take our cartoons way too seriously, especially Dragonball Z.
I’ll watch pretty much any cartoons that are on, although I don’t understand the attraction of Ed, Ed and Eddy.
One question, though. At least one person in this thread, and others on the board have mentioned that their kids watch Samurai Jack, which I feel is the most explicitly violent show on TV right now. Which is one of the reasons I love it. But how old are these kids that watch it? I’m not sure I’d want an eight-year-old tuning in.
At lunch today, I was mentioning to someone that the only shows that I watch are either cartoons or sports.
The cartoons that I go out of my way to watch are:
The Simpsons.
Family Guy.
Samurai Jack.
Justice League.
Futurama.
Cartoons that, if they are on, I’ll watch:
Spongebob Squarepants.
Batman Beyond.
Dexter’s Lab.
Southpark.
Batman: TAS
Cartoons that I wish were still on:
The Tick.
Duckman.
Earthworm Jim.
Star Trek.
Pink Panther.
The best cartoon never was Science Court (forget about Squigglevision and the other nonsense).
After all these years, Hanna Barbera actually made some great cartoons in Powerpuff Girls and Dexter’s Laboratory.
I meant “best cartoon ever…”