It depends on how you're traited.
Before I got the trait(Beastmaster's Bond) that grants me Fury and Might when pet's health reached 25 percent, I liked my pets to take little damage. I used ranged pets like spiders and devourers. Now that I have the trait that grants me fury when my pet reaches 25 percent health I want them to take damage quickly and be effective while they're doing it. With the new verbal queue and ability to call your pet back to you, you can either switch them out or get them out of combat before they die, since you hear, "I won't let you die" when they get to 25 percent health. Now I use the Krytan Drakehound since it has a 2 second AOE immobilize on a 20 second cooldown as well as a knockdown and a cripple. The other pet I use is the River Drake since it has two AOE moves(a tail sweep and a chain lightning). The chain lightning does huge damage especially to a zerg.
The ranged pets are great because some of them create a poison combo field.
It all depends on your build. If your building for condition damage I would take ranged pets, bleed pets, or the Drake that does fire damage. If your building for direct damage I would take the Beastmaster's Bond trait that grants Fury and Might at 25 percent pet health and a couple of pets that will be effective while they live and reach 25 percent health quickly.
If your playing a support class or healer ranger you might want a White Moa, Red Moa, or Fern Hound since they grant buffs to your party.
If you're building to stack bleeds there are several pets that are effective at stacking bleeds.
What does your build look like? I played Ranger throug all the BWE's and stress tests. I learned that the pets are very situational and build specific.
» Edited on: 2012-08-17 19:19:43