As has been already said it is Dragonscale or nothing for a Hunter, unless of course you already raid and do the top instances , if you already are able to do them you could pick one of the others as its going to be either buying a lot of things or doing a lot of grinding to get the mats anyway.
As it is , at level 70 it will take ages before you can make anything that is better than you have already , and then it is only a few items worth having , but if you wanted to do one the others for an alt it would be worth taking one of them up as they would be getting a nice boost.
Personally as a Hunter i like the skinning and did go Dragonscale but found hardly anything better than i already had , it is more patches and a few other pieces i make to get my level up ( the last levels are a real pain in the butt anyway ) but at least the top end stuff will get you into instances with reasonable gear if you do not already have good gear.