ooh, this is a tough one! i'm a big fan of cartoons, i grew up watching absolutely nothing but cartoons, so to pick a favourite is... pretty difficult.
though movie wise, i'll have to say the lion king 2. i loved the first one, but kovu and vitani are some of my most favourite characters ever, so i place the sequal a little higher than the original.
t.v. show, at the moment it's probably my little pony: friendship is magic. i love the colours they use, the characters they have, and although it might have a few mistakes time to time, the animation is really smooth and enjoyable to watch.