As a new 80 (or tanking on the way to 80), I'd probably go for a few more of the bear talents.
Here is a spec that might be good until you decide to go full-time one way or the other.
[spell]Master Shapeshifter[/spell] is cool, but for bear it's not as necessary (we generate good threat without it); I also raided a long time without it in cat, and still did quite nice dps (if I do say so myself). Recently I have switched to a much more raid-focused dps spec so I grabbed it. If you really want to have it, I'd take 3 out of [spell]Predatory Instincts[/spell] and 2 from [spell]Improved Mangle[/spell]. But my gut feeling is you'll lose a lot of cat dps if you do that.
Most folks are only going for three in [spell]Furor[/spell], since it works differently now. Just shift in and out of bear until you get rage before you pull. Really isn't needed to have 5 for cat.
[spell]Improved Leader of the Pack[/spell] is awesome for soloing, but if you have a dedicated healer it's not necessary.
That frees up a lot of talent points to throw into bear talents. I put 3 into [spell]Protector of the Pack[/spell] because I think 4% more reduction in all damage is better than 2% more dodge ([spell]Natural Reaction[/spell]), and [spell]Survival Instincts[/spell] is a really nice panic button. You'll still have most of the cat stuff (if you decide to go full-time cat you will LOVE [spell]King of the Jungle[/spell]) and should be able to do good dps, but I would think a spec like this would let you tank well too.
You could also take one point from Predatory Instincts (since it is cat-only) and put it in Natural Reaction to fill that out.
Caveat emptor: I did sort of pull this spec out of thin air, so you might want to check around for better advice.
For starting out in heroics you'll need every advantage you can get. With the new Dungeon Tool, people are very impatient with marginal tanks, so you want to be as prepared as possible. You also have no idea if your healer just stepped out of ICC 25 or is still shooting off the last of her "Welcome to Level 80" Dalaran Fireworks. As your gear gets better and better, you can start taking a few points out of the specific bear talents and put them into cat talents because when you and your healers massively overgear an instance the spec doesn't matter that much. I haven't tried lately, but I can probably tank everything up to Heroic Halls of Reflection in my pure cat spec and cat gear.
They really tried to destroy the hybrid bear/cat spec with the last talent rebuild, but for heroics you should be able to still get a pretty nice taste of both worlds. If you decide to raid this might be a viable offtank spec, but your dps will not be all that awesome compared to other raid-specced dpsers.
Happily for gearing purposes, "tanking leathers" and "dps leathers" are essentially the same now. There will be items with more stamina than others, and weapons are slightly tinted toward one purpose or the other, but gear is pretty easy to find now. Just grab what your cat wants and stuff it with stamina gems instead of agility. Having the [item]Polar Vest[/item], [item]Polar Cord[/item], [item]Polar Boots[/item] and [item]Trollwoven Spaulders[/item] made by a friendly Leatherworker will start you off with very good tanking gear until you get enough badges for Tier armor.