My new favorite build for MP0-5 solo farming:http://us.battle.net/d3/en/calculator/demon-hunter#ichgVd!ZbX!abZYcb
Elemental Arrow - Ball Lightning for 90% of the mobs. This skill melts trash packs up to MP5 very quickly with my DPS and I don't run into hatred issues with enough health globes and my companion.
Rapid Fire - Fire Support for destruction of single targets and elites. This skill is very powerful but for more regular use I would suggest the Withering Fire rune.
Companion - Bat Companion for hatred regeneration in this zero hatred generator build.
Shadow Power - Gloom is still the best defensive option for PVE in the game.
Preparation - Backup Plan for extra discipline. This build assumes non-legacy Natalya's and a lot of use from Vault so others may substitute this for another skill of their choice.
Vault - Tumble for massive mobility. I use vault every 2-3 seconds on average probably when moving around between packs.
Tactical Advantage is required for great mobility to increase efficiency overall.
Vengeance is required to maintain the hatred level necessary for this build. The extra discipline is great too, but you need at least 14 yards of pick-up radius for best results.
Nightstalker is optional but recommended to maintain high mobility with liberal use of Vault.