Two great pages that will help you:
http://wow.allakhazam.com/db/class.html?wclass=5;mid=119399640888197052;num=29;page=1
Yes that IS the sticky, and there IS a reason why it says "EVERY QUESTION ANSWERED HERE", so READ IT, people did a lot of hard work and spent a lot of time doing the stickies so there wouldnt be thousands of threads like this, so dont throw their work into the trashcan.
And
http://petopia.brashendeavors.net/
That's petopia, my friend, a hunter's best pal ever, and an interesting webpage even for the nonhunter.
As far as pets go, boars would be your best choice untill higher levels, when you can get dash on raptors/cats, prowl on cats, Gorillas, etc.
Why? because boars are very balanced pets, and they have amazing HP, wich is great for tanking, they also are the ONLY pets in game to have the Charge ability, wich is amazing in PvE to get to targets fast/runners, and cant be better in PvP.
Now lets see, talents...
I believe you should go the Beastmastery way, IMO its the most effective way of leveling, since you will hardly ever get hit, and will be available to kill many elites/solo group quests. You WILL rely heavily on your pet, that's why the tree is called BEASTmastery.
There is another choice, wich I also like and Im trying currently with my hunter, and seems to work pretty well:
you can start out with 5/5 Lethal shots in the Marksmanship tree, for +5% critical strike chance with ranged attacks, wich is amazing for a low level, then you can grab 3/3 hawk eye, in the Survival tree, wich will give you a total of amazig 41 yard shooting skills, wich will help in PvE for super long pulls, and give you a couple more seconds to run if you get aggro (wich you wont if you are beast master) and is extremely cool in PvP, after those 8 talent points, you should go straight up the beast mastery tree, and try your lvl 48 build to look something like this : http://www.wowhead.com/?talent=cV0G0gxRVzZVZ0h
It leaves 1 point for you if you plan to PvP at 49, and still leaves you with +5% crit strike chance, 41yd shooting, and bestial wrath.