Once your Barbarian reaches level 70 (perhaps with a help of a leveling build), you will be in a prime position to pick and work towards your Build. Keep in mind that your Build will not only define your gameplay going forward, but also your optimal armor and weapons.
Below you can find some of the best Barbarian builds for Diablo III.
Raekor Boulder Toss
This build gives the Barbarian somewhat of a ranged option while dealing large AoE damage. Damage on this build will primarily revolve around Ancient Spear, assisted by Furious Charge and Weapon Throw.
LoD Hammer of the Ancients
(LoD refers to the Legacy of Dreams Legendary Gem)
A fast hitting, tanky build that is capable of dealing large AoE damage. It does not rely on any sets, but rather a few legendaries to enhance your Skills. Damage on this build primarily revolves around Hammer of the Ancients.
This fast-paced build keeps things simple but effective, having a focus on slashing enemies and using all of your Shout Skills. Damage on this build will primarily revolve around Frenzy.