My friend wants to build a gaming pc for around 600$.
-He has a monitor, cd/dvd reader, case, and a good enough psu for what his budget can get him.
-He doesn't mind gpu/cpu brand.
-He will be using it mainly for FPS games.
-He wants to run BF3 on decent settings.
-If it's possible, he wants a pc that can be upgraded in the future (sli, add ram, etc.)
I think his best bet is an I5-2400 with an h61 board, 8gb RAM and something like a GTX 560ti. SLI isn't always a good upgrade option, I would only recommend it if he plans on getting the second card in 6 months or so. Sorry I would get the links but I'm on my phone.