If you're gaming at single 1080p, personally, I think the HD7870 XT is the best value card. Overclock it and you have a card that performs close to an HD7970. Don't forget, it's around $40-50 cheaper than an HD7950. I suggest you get the HD7950 only if you're planning on gaming at multiple monitors or higher res (ie. 2560x1440/2560x1600).
Ive been toying with the idea of buying a 7950 or a 7970 and selling the game codes for ~$50 each. That would make a 7950 "cost" around $200. There should be a big enough ebay/craigslist market for the game for sure. If you want to you could consider that option. I know the 7870's also come with games but I expect more demand for crysis 3 rather than tombraider. This is of course assuming you were not going to play the games when they release.