stat priority for barbarians
I would say that stat priority for barbarians is as follows:
Weapon DMG (probably best stat for all classes in Diablo III accounts, almost all abilities have their damage based on it) > % Chance to Block (best stat for shields) > % Life (depends what % it is of course, as an example I would say that you just NEED to have helm with socket as barbarian) > All Resistances (until caps for each act that I mentioned before) > Vitality=Strength (you need to balance those stats around so that you are able to both survive and kill stuff, if you have for example twice more vitality than strength then you are doing something wrong) > Fire resistance=Physical resistance > Armor > Attack Speed % > Life on Hit > Life regen.
Keep in mind that it is hard to state the definite stat priority. Everything depends on the build you chose and how you play. As an example, your life on hit will be useless if you don’t have decent amount of attack speed to buy Diablo 3 items. On the other hand, a lot of attack speed without some life on hit stat on your gear might prove to be a lot weaker.
I would say that you need at least 40k+ HP in later inferno acts (act 2 and above that is, you might be able to do the first act with 35k+ or something a bit lower). Once in act 3 and 4, you should have somewhere around 40-50k HP (maybe even more, up to 60k - if you stack more vitality along with % life).
As for damage, as I said before - stacking ONLY defensive stats and buying items with only Diablo 3 account buy vitality on them is bad. You need some STR (it also gives armor!) and you need some DMG. In act 1, something like 5k damage should be enough but later on if you will be below 8-9k dmg, then you will be having problems for sure. You need to have AT LEAST 8-9k damage for act 2 and 3, preferably more. So if you see that your target is simply not dying, try to get a new weapon with more dps or even replace some vit with str (or even play around with your build and replace some defensive ability with offensive one).
Also remember, that having some life on hit is nice and helps a lot. It is sometimes better to lose 100 DPS on your weapon at a cost of getting 200-300 life on hit stat. I would say that for acts from II to IV you will need somewhere around 500-1k life on hit. If you can't get your hands on weapon with loh then try to buy some rings or amulets with it (decent weapons with life on hit tend to get really, really expensive).
At this moment in time, % AS is undoubtedly the best DPS stat for all classes (especially barbs that are stacking LOH). If you stack attack speed on every possible piece of gear, your dps increases like mad. So why not stack it? Well... because it will get nerfed to the ground soon (it was already confirmed by Blizzard in one of blue posts). It is insanely OP indeed... for now. I suggest getting % AS just on your neck and one ring. Focus on str/vit/+all resists on other pieces of gear. That way you will avoid DRs once patch hits.