Asking which pet is best is rather like asking what flavor of ice-cream is best. *smiles* Its largely a mater of opinion. For the best source of pet information, head over to Petopia (http://petopia.brashendeavors.net/) and look at the various pets and read the articles you can find there. Also check out the sticky at the top of this forum. Page one will give you all kinds of information about hunters and page two will give you all kinds of information about pets.
For my own personal opinion, if you don’t have a particular type of pet that you like:
1) Boars are very good pets. They get the very useful charge skill at level 10. They can also learn both bite and gore. If you follow the beast mastery tree, gore becomes extremely useful once you buy the pet skill that allows your pet to regenerate its focus faster. Boars are also fairly tough little buggers and they will eat almost anything, making them easy to feed. They can also be found near the starting area of most hunter races and come in many different colors.
2) Bats, owls and carrion birds also make good pets if you can stand having a flying pet, which I personally can’t. But these birds can learn Screech. It’s a small area effect ability that generates extra agro. So these pets are very good at holding agro on multiple mobs. Of the three, I’d recommend the carrion birds because for a solo pet they have more rounded stats and they have a slightly better diet.
I would also like to add that for beast mastery hunters, any pet will work. One of my level 70 hunters has a pink tallstrider for her main pet. Tallstriders are rather picky eaters and all they get in the way of skills are bite and dash. But the fun I’ve had with her as a pet has far outweighed any lack of skills. So feel free to try out different pet types. And if there is one pet type out that that you would really enjoy having at your side, go for it and don’t worry too much about its skills or lack thereof.
Good hunting.