There is a lot of combination on a paladin set, which will depend what you planning to hunt.
If you are hunting single target, my recommendations are:
Bow - Powerful Strike + Powerful Vampirism+ Powerful Void (All Tier 3 of Critical, Leech & Void))
Helmet- Powerful Void & Powerful Precision (Tier 3)
Personally I felt that having two life leech for single target was a waste of the money.
If you are going for team hunt and multiply target :
Bow - Powerful Strike + Powerful Vampirism+ Powerful Void (All Tier 3 of Critical, Leech & Void))
Helmet- Powerful Void & Powerful Precision (Tier 3)
Armor: Powerful Vamprirism + (if needed) element of the protection as fire/ice/earth/death/holy/energy) depending what u hunting.