You know, this is an interesting question.
I introduced some classic cartoons a while ago, some vintage Felix the Cat. Kiddo thought it was really creepy-- it had some great animation, flowers and trees that moved--- but he didn't like it. This was when he was five. He liked Felix as a piece of art and I have a nice picture in my kitchen of that from him.
When our boy was six, we let him watch Scooby Doo. We've had mixed results with this. We learned-- through watching with him and listening in-- that the earlier Scooby Doo's are the better ones. The stories don't go into boy/girl dating stuff the way the more recent ones do. All this said, Kiddo did have some nightmares and was extra clingy around this time, so we decided to take a break on Scooby for now.
My son's favorite cartoon by far is the Ninjago series. He loves it in that deep way he has loved dinosaurs and vacuums and pumps... he wants to know everything about it. He was also introduced to SpongeBob, who makes me cringe and can drive me from the room.
He's still not interested so much in Looney Tunes, but did say he'd recently seen a Bugs Bunny cartoon on a trip with his dad and thought it was funny. I think there needs to be some silly in every kid's life, and those cartoons are really silly. My son watches Ninjago and is actually a very mild kid as far as that sort of play. I figure that I watch tv for pleasure, and he does get a fair amount of more 'educational' media exposure as well-- he should be able to have some say in how he spends his limit of media time. He's almost seven and has been showing real responsibility in turning the tv off when his shows are over. It's been nice to see... they do grow into it. :)
Queen of the Castle: Thanks for the laugh! I haven't ordered anything from the acme catalog either....