Well! Obviously the first thing to look at is how to spec your druid for maximum... tanking... awesomness! So for level 80, there are basically two different talent trees you can go with.
This is the spec I run with. It is pure tank, no kitty-ing about. Pretty straight forward. Glyphs are all but a no-brainer because they're really the only ones that will have ANY effect on our tanking. I actually just switched to this spec from a VERY slight (2 point) differential, and I'll explain why after the 2nd screenshot.
So the only difference between these two specs are the points I moved out of Feral Aggression and into Primal Madness... currently I am running with the points in Primal Madness. Initially I liked the idea of having a 1-time three stack of Faerie Fire for the DPS increase... I still do like that, to be quite honest, but the reason I moved to Primal Madness is for trash packs and 5-mans. The extra rage generated by our Enrage ability makes it so we can almost swipe as soon as we pull a pack. It also makes it so we can start our rotation more quickly on boss encounters.
I've been questioned a few times on my choice of the points in Brutal Impact. I suppose you could make the arguement that the extra interrupts are situational but DAMMIT if I don't like having them, because i've spent so much time tanking WITHOUT having worthwhile interrupts... and no, an interrupt with a stun DOES not count, because you can't pull mobs towards you when they're effing stunned. The other thing you may ask about is why I only put 2 points in Fury Swipes... Druid threat isn't in a place that's hurting in any way right now on single targets. 2 points procs plenty enough, and our threat is insane after the first 5-10 seconds on a mob.
So, assuming all of these things (and assuming Brutal Impact, if you're like me) then let's move forward into tanking at level 85. Not a lot is going to change from your level 80 spec. No real need to change specs unless you want to test weird things out, so I came up with basically 2 different level 85 specs.
This first one you'll see that I have a spare talent point available. The reason for this is I figure it's kind of your "do whatever the fuck you want with it." If you want to go with max TPS For that point, put it in it should probably go into Stampede. Honestly, though, the TPS generated by 2 points in Stamepede, let alone 1, is hardly worth the poinst from a pure tanking point of view. A point in Feral Aggression could be handy to 2-stack FFF instead of 1-stack. One point in Perseverance (in the resto tree) for a bit of extra spell damage reduction, but that's properly a bit situational... which brings me to my second tree below.
This tree doesn't have any spare points, and honestly I wish it had just one more talent point to finish out Perseverance in resto... but as I mentioned earlier, this could be a very situational setup to have. It really just depends on how many bosses in Cataclysm deal random magic damage, and whether 4% will really make that much of a difference.
Now.. With all of this stuff I want anyone reading this to realize a couple things.
First - I am not in the beta. My lvl 85 druid builds are purely hypothetical based on my experience with druid tanking post 4.0, and with what I know about how the theorycrafting works behind it.
Second - I am no 100% expert. I could very well be proven wrong about some of my ideas. They're not set in stone by any means, and I am not proclaiming them as such.
Thirdly - I am not responsible for your fuckups. I *can* help if you'd like, but if you tell me that my spec sucks and you can't get shit to work with it, then well.... your mileage may vary. I'd be more than happy to compare notes with you as long as you're not a shit-stain about how you approach it.