Help With a Build For a friend

Okay, So my friend wants to get into pc gaming with me but he doesn't want to spend more then $600. My other  friend and i have a case and a PSU for him so he wont need those.... He want to be able to Play Bf3 and dayz stand alone (when ever that may come out). I was gona pick out the parts for him but I'm having trouble staying within his budget. And am also unable to chose between AMD or Intel. I could really use suggestions anything will be greatly appreciated!

AMD usually provides a better bang for the buck. What kind of PSU do you have already? And does your friend need an OS?

And what form factor?