No point in getting two previous generation cards e.g. 6870. Get the best card you can afford now and then you can buy another down the road to meet future gaming demands. Think ahead!
Also the board says it supports nvidia SLI but does not mention Crossfire. It might be worth considering a mobo upgrade at some point. It only supports 8GB DDR2 RAM @1066.
Yeah fizzle22, I've been considering upgrading to a different motherboard + cpu + memory + graphics card. It would cost me around 800 bucks if I wanted an i5 and a 7870 with a board and memory which really isn't terrible but I'm just seeing if I can get away with just a graphics card.