What card for 3d modeling, rendering etc?

Im building a new pc shortly and would like to ask a few questions.
What the whole build is being based is dealing with programs like blender, photoshop, and sony vegas just to name a few.
I tried searching on google but haven't really found a answer to help me decide. Mainly I can't choose what would be the best video card to suit my needs. I'm thinking of these three:

7870: http://www.tigerdirect.com/applications/SearchTools/ite...
670: NOT SURE OF A GOOD CARD? (brand)
or
7950: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Im using atm a single 24inch 1080p monitor and have plans to add a second after. I do enjoy overclocking gpus, which is why that 7870 has my eye   . I do game so that is also a concern and i know all 3 would be more than what I need, so the main problem is. What card would be better in assisting me with 3d modeling, rendering and stuff along that line. If it matters I will be doing lots of animation and coding. So with all of that in mind, what would you recommend as a gpu?

Panamera.