To me, our options for a bear-tank spec at 85 seem rather limited. As far as "baseline" goes:
31 Feral/9 Resto + 1
This includes all survivability talents:
Feral Swiftness (T1): 4% dodge
Infected Wounds (T2): 20% attack speed slow
Thick Hide (T3): Armor bonus and crit immunity
Survival Instincts (T5): cooldown
Natural Reaction (T5): passive mitigation
Perseverance (Resto T2): passive spell mitigation
(Leader of the Pack (T4) has some small survivability gains, both from the heal and crit bonus to Savage Defense. But they seem to be secondary to those above. Then again, it's only one point; you should be taking this regardless.)
Now there is probably a bit more debate about threat talents. But, since you have to take so many anyway to get all the way down the tree, you're really more choosing which talents to
not take. In my case, I've passed on two cat-only talents (Predatory strikes (T1) and Blood in the Water (T6)), and King of the Jungle (T3), which would be excellent for threat if Enrage didn't have that pesky 10% damage increase.
I would, of course, be interested to hear other takes what talents to skip.
And, finally, note that if you're looking for some sort of "offtank" or "hybrid cat/bear" build, that would look a bit different.