I'm still debating between the two cards.
Amazon has the Sapphire HD 6870 in 165$ (which is actually great because i only have 200$ to spend) and the EVGA GTX 560 is 180$ (plus 10$ i have to spend in a HDMI to Mini-HDMI cable)
So far i've seen that both cards are quite similar, theoretically, the HD 6870 is a little bit better, but i don't know how that translate into real world scenarios, the only thing that stops me from buying the AMD one is the fact that i've been using nvidia for the last 5 years so I kinda got used to it!
My mind is telling me to spend a little more and get the GTX 560, plus... The "Duke Nukem Fully Loaded Package" is 185$ in Amazon, it has a free Duke Nukem Forever game, bet buckle, limited edition design and a mousepad
I'm still debating