Playing around I find myself keep coming back to this build or a build similar to it.

http://us.battle.net/d3/en/calculator/demon-hunter#ebdZSX!cSh!bZcZcc

Actives:
Entangling shot: Keeping distance is key, so slows are a must.
Golden rune: As this is my only hatred generator I need to make the most out it by
generating more per attack

Caltrops: Same idea. Keeping distance from the mobs
Crimson rune: Additional damage is good, however I'm not married to this choice. Indigo
or obsidian are good choices as well.

Vault: I can't expect so stay out of the fray 100% of the time, so I need an out so to speak. The idea is I would use this along with caltops. Lay the trap, vault, then pew pew.
Obsidian rune: Lay down some hurt while I fly away.

Impale: Solid skill with good damage.
Crimson rune: Certain targets need to take priority and sometime these targets are in the
back behind everything. I'm talking about the skeleton mages that res more skeletons or
the wretched mothers that vomit out more ghouls in the beta. These need to be taken
out. So, giving this solid ability allows me to pierce through all the mobs to get the one
I need to kill.

Multishot: Diablo is all about fighting hordes of bad guys. You have to have a good area ability.
Obsidian runes: Rockets! I have no idea how these will play out, but they sound pretty
cool.

Rapid Fire: Mow them down! I also see it being good to unload this onto a powerful single mob as well.
Obsidian rune: More rockets!

Passives:
Cull of the Weak: This build centers around keeping enemies slowed, so it just makes since to increase the damage on those slowed enemies.

Ballistics: Since two of my abilities are runed with rockets, it only makes sense to increase that damage. Otherwise I think the rockets would be kind of useless.

Sharpshooter: Steadily increasing crit could be good. Steady Aim or Archery may replace this.