In the past, shields were considered detrimental to DPS because of the block animation. It stops you from continuing with an attack animation, thus cutting the damage output quite a bit for an insignificant gain in protection.
With that said, I really enjoy 2h weapons with the Barb. However, after learning his skills and equipping two 1h monster weapons(the Barb's exclusive weapon class), dual-wielding is very viable now. It speeds up the attack rating from what I have seen, thus increasing output of damage quite a bit.
That is not dead which can eternal lie, And with strange aeons even death may die.
I think it really depends on the rest of your gear and what stage of the game you are at. I used to dual wield, but I'm finding that a single strong 1h and a shield with about 20% block is working better in inferno
Big argument here ... I have a barb level 57 ... I have used two handed ... One handed with a shield ... And two one handed ... The two handed will hit harder per attack but very slowly ... But the two one handed will hit for a little over half the damage (compared to two handed), you hit 2-3 times faster than a two handed .. Plus you get the extra stats from an extra piece of equipment ... On the other hand the shield offers very valuable defense ... It really comes down to your personal preference
I'm finding that a high DPS 1-handed weapon is good with a shield that gives +Str. You're still increasing your damage with the shield with the Str boost, and you're getting the defense and block boost. Also, a lot of shields have +Magic Find, so if that's important to you, definitely go shield.
Captain Falcon used his Aerial Forward + A move while wearing a bee costume. It was the bee's knees.
Unless you have some 2h with absolutely insane modifiers, you will almost always be better off with two 1h weapons or sword n board.
Your DPS value will be higher with 1h weapons, but your damage per hit will be drastically higher with a 2h weapon. The higher the damage% of your barbarian skills, the larger that gap becomes. So if you use runes that boost your damage%, you will deal far more damage per hit with 2h than a 1h. Your DPS value doesn't matter if all it takes is a single hit to wipe out a group of enemies. Also your most powerful skill, Earthquake, will be far more powerful with a 2h weapon.