Honestly I would get a single card for better upgradability later. If you get a 7850 now, you can get another later.
I don't really upgrade often hence the jump between 4850 crossfire and just looking for upgrade now.
Could you give me some more options for a crossfire or SLI setup.
Actually now that I look at it the price for 2 560s is going to be around 300, so what will give me better performance 560 SLI
or a single 660ti.