I have a slow-centric build at the moment. You can check it our here:
http://us.battle.net/d3/en/calculator/demon-hunter#bRXVlc!abc!ZZZbaZ
Probably not ideal, but it's fairly good for not having all the runes unlocked yet. It's got a bit of synergy. Personally I think the Lighting Ball Elemental Arrow is kind of weak in comparison to the Frost Arrow I'm using, which is also good for single targets.
I was doing a sort of kooky thing before with cluster arrow as the primary hatred spender, which is kind of interesting, but won't really be viable at least until you take the passive that reduces the cost. It had super high concentrated AoE (also great for single target) burst damage though.
So many viable builds...
I'm using Bola (electric shock) as primary and Impale as secondary (Impact). Keeps enemies stunned so I can run away if I have to. My primary hatred spending is still multi-shot which I have on R. W is always vault and Q and E whatever I feel like. Right now its ferrets/sentry (at level 45)