Best Armor Stats for Barbs

Extra physical defense is good, but try to look for some HP bonuses/vit. bonuses along with these.
Extra elemental defense is decent, but like I said, we're mainly looking for the HP bonuses.
The reduction of physical damage taken isn't too good, I would imagine.
I've never considered once about getting an evasion bonus. Although I guess it would help when tanking.( Less damage taken )
Hp recovery is decent in the beginning, but later on, getting HP recovery mods. are pretty much useless as long as you have a tanker build.

Use citrine shards.

I would use HP shards as Def Shards won't do much against magic mobs

Well for me, in order:
1. +HP and/or Vit (whatever gives you more HP)
2. +Str and/or Dex (or for arms, attack speed if u can get it)
3. +Elemental resistance (especially wood and metal)
4. +phys damage reduced by X% (If you have high def, how much more do you need to increase reduction by 1% even? think about it.)
5. +phys resistance
6. increased movement speed? I dunno, don't really look at any other adds after all of these.

1. +vit bonus (HP, HP regen, pdef and mdef. Whats not to like?)

2. hp bonus (Just HP, but can be quite a lot of HP)

3. +str or +dex (especialy useful if you are a tank build and want to up accuracy or squeeze out every last bit of vit)

4. elemental resistance (Magic is our main weakness)

5. extra phys def (useful upto a point. Once you have 10k pdef, more pdef is kinda pointless)

6. reduce phys dmg % taken (reduces % damage you take after your pdef damage reduction has been applied, so is usually not a lot. For e.g. with 2% reduction it will reduce 6dmg on every hit of 300 HP)

7. +hp recovery (if you have a tank build or lot of +vit adds you generally don't need this. But it does help cut down meditation time)

8. evasion (I didn't find evasion of much use. I saw a few misses until the 40s, but not many after that. Its not something I would look for, but if its an extra addon, why not?)