Pets! We all love them, it is the reason most of us chose to play Hunter. There is one very useful site for information on pets: http://www.wow-petopia.com/
get used to using it for finding pets, updates on pet abilities and even the new spirit beasts!
Marksman and Survival Pets:
The beauty of the pet overhaul some time ago is that we now have a pet for every occasion. In addition, we now have the ability to swap our pets in combat – meaning that with thought we can have a pet to counter whatever comp we come across.
The usual pet line-up for non Beast Mastery hunters will consist of some of the following:
Monkey – Gives a 4 second disorient, (however counts as controlled stun that cannot be blinked out of).
Scorpid/Bird of Prey – 10 second disarm (1 minute cooldown).
Moth – 4 second lockout (1 minute cooldown).
Spider – 5 second root that does not break on damage (40 second cooldown).
Wind Serpent – Increases magic damage taken by the target by 8% (great for Survival Hunters or if you are playing with a caster, that is not a warlock).
These 5 pets together provide a well balanced group of pets that can be used to increase the utility of your team.
Beast Mastery Pets:
Core Hound - provides bloodlust and a casting speed debuff.
Spirit Beast – Provides a heal (scaling with attack power) and an equivalent Horn of Winter buff. (Multiple Spirit beasts is highly recommended for double DPS 2s as the heal cooldown is not shared among the different beasts).
Side notes: There are many other pets that give a variety of debuffs, mostly for PVE purposes, in certain situations where you might know who you are facing (such as a tournament) you may find these other pets to be of better use. I highly recommend using http://www.wow-petopia.com/
regularly, add it to your favourites and have a browse through the various pet abilities.