My Little Pony. Yes, I'm a brony, and yes, I will go on and on and goddam on about why I like it. Because I have that kind of time on my hands.
Just so you get an idea where I'm coming from: I'm 23 years old, male, and in the Army, currently deployed to Afghanistan. Look at the comments for the first few episodes on Youtube, you'll find many, many other guys like me.
I've been trying to pin down what I like about it so much for a while, and I think I just about have it. It has a certain wit and simplistic charm that I haven't seen since the likes of Animaniacs. High praise, indeed.
The theme song is enthusiastic, and you can tell the women singing it aren't phoning it in, something that is disturbingly common in most modern kid's cartoons. The art is soft and easy on the eyes and the animation is fluid. I understand some people have a problem with Flash animated cartoons, but I think this is an example of how it can be done well. Shoot, I had to be TOLD it was Flash. It never allows itself to get overly "girly" or completely vapid like the earlier incarnations of MLP (I've only seen satirical reviews of the movies).
The characters are all distinct, if maybe just a tad cliched and one-dimensional, but I think that's to their credit. 14 minutes into the first episode, I knew everything I needed to know about the main characters, and their names were permanently ingrained in my brain. I can watch whole movies and never know ANY of the character's names.
Speaking of characters, I made a point in the "worst cartoon" thread about the straight man, the sane character that's supposed to somewhat represent the viewer, and Twilight Sparkle fits the bill rather nicely, I think. Besides, with the sheer diversity of the main characters' personalities, there's something to like in all of them. For example, Fluttershy and Pinkie Pie are the sweetest, cutest things in the multiverse. Kittens make your head explode into candy, Fluttershy makes your head explode into rainbows and sunshine.
Even the morals are largely unobtrusive, aside from the aesop that takes up the last minute of the show, but even then it's never some inane, insipid trite about "friendship are teh best thing evar."
The comedy is generally a mix of character quirkiness and some light Looney Tunes style slapstick, and it works. Also, heroic BSoD moments are ALWAYS funny. Except when it happens to Pinkie Pie, which just makes her scary.
As for the fanbase... well, there's almost always a very weird, sometimes scary sect of a fanbase that takes this WAY too far. No true Roman argument aside, it's not difficult to just ignore them.
So, you know... best new kid's show. My Little Pony: Friendship is Magic.