Well, I don't have any of the math threads relating to these pets bookmarked, and I'm too lazy to dig them up, but it pretty much said Ravager over Cat over Raptors. Still, the difference is unimportant and won't really matter to anyone that isn't an elitist little sod really...
My advice is that you pick the pet that you feel like having. Don't discount the feeling of comfort or sheer badassery of having a pet you think is awesome. That feeling will inevitably provide contentness and self-esteem, which will in the end increase your personal performance since you won't be lowering both your expectations and attitude.
This is all slightly philosophical and so on, but I've found as a Classleader for Hunters that increasing my Hunter stable's performance is done more by increasing their self-esteem, attitude and morale than by nitpicking over their speccs, pets and enchants. Of course, all the math stuff helps, but the main thing to think about when you play is that you, the player is the main source of DPS. You just won't have a spreadsheet readily available to show the math on it.
So, go for a cat, ravager, raptor or whatever you feel like as long as it is a DPS pet, and go kill those bosses.
Oh, as for pet skills. Just give them Claw/Gore and Bite. Depending on your specc you should have at least one Focus generation talent that will allow you to dump pretty much all the time. That math has been done in the past, and I see my Humar doing more damage with Bite than without.
Edited, Nov 29th 2007 8:43pm by NorthAI