Yeah you can max out bfbc2 with your 580's, but i can also do it with a single 570 and still run at 60 fps. Dont get me wrong, I would love to have your set up, but one card is sufficient for now. However if the sli 560's are in your budget... do it, Id say its almost always worth future proofing a build when possible.
Also, you wont need 1000 watts, something like a solid 850 would do fine.
you dont need 1000w for a start. an i5 2500k 2x560ti's and a good 750w Antec, seasonic, corsair or XFX power supply is what you want. Dont go for the cheap brand PSU's. Even some of the more well known brands like thermaltake or coolermaster make some pretty crappy PSU's which will not produce their rated power.