Level 40 used to be when you get your mount; now you're just going to pick up Trueshot Aura and your epic mount if you can afford it. You also learn to wear mail armor.
Skills, Level 40:
- 40: Aspect of the Pack, Freezing Trap (Rank 2), Hunter's Mark (Rank 3), Raptor Strike (Rank 6), Track Giants, Trueshot Aura, Volley (Rank 1)
Level 40 also gets you Giant Tracking, useful for several quests looking for wandering giants. A lot of giants in Azeroth are still roaming elites, too, so this can also be used for avoiding getting smooshed.
Trueshot Aura, your talent point, is a 10% AP boost. It is no longer a 30 minute buff, but it does still turn off when you die. It will get temperarily overwritten by Enhancement Shamans' and some Death Knights' 10% AP buff procs, making the glyph for it less useful in raids, but it's still a good buff to have overall.
Volley is your last new level 40 skill, and it is great. Even if you're leveling with a tank pet, you're probably going to be pulling aggro off it by now, but if you're careful about it, you can start doing some AoE fighting. Combine it with an Explosive Trap for extra oomph. When I was leveling my baby hunter, this is the skill I was impatient to pick up.