Overall, I would prefer humor, or possibly action combined with humor. I enjoy comedy, particularly smart comedy, which has to be more than just abstract craziness, although some over-the-top zaniness is enjoyable in small doses.
As far as stars go, they don't have to be 100% squeaky clean law abiding citizens, but that must at least be likable enough that you care about what happens to them. It's hard to want to follow a show where you don't care about any of the characters on it *cough-American Dad-cough*.
Generally, I would prefer to see more shows about humans, mainly because there aren't as many of them. However, I could stand a show about cartoon animals, even anthropomorphic animals, just as long as they aren't anthros acting under the belief that they are human, by that I mean animals who are so humanized that they own pets and go to zoos and have human anatomies. If they're going to be that humanized, then make them 100% human characters. But please, not another show about a crazy animal and the level headed boy that he lives with; there are already too many shows built around that premise.
Also, I'd like to see more shows starring ethnic protagonists. Not a 30 minute preach fest about being accepted and getting along and promoting pro-social values, just more shows about regular people having crazy adventures who just happen to be black, Latino, Asian, etc. I want to see more ethnic superhero/magical beings (And executed better than WB's Static Shock). Where is it written that all main characters/super heroes/magical beings have to be white? And not so many reinforced stereotypes; some Latino characters who don't wear luchador masks and talk like the Frito Bandito. Some more African-American characters who don't play basketball and talk like wanna-be rappers.
Basically, that's what I'd like to see.