I would like to build a nice computer that would be able to withstand world of warcraft on high graphics and others newer games on a low or medium setting, I prefer AMD but ill work with anything, I do not need a mouse, key board, monitor, Ect... Just the tower and its internal parts, I would like to have a quad core and 8g ram if possible, big also a great video card, thanks
I think you will be hard pressed to plan ahead for crossfire at your $500 budget. The below build accounts for your requirements other than price. If you need to bring the costs down I would suggest going with a motherboard with only one PCIe 16x slot and scale the power supply down to around 500w.
I agree with getting the FX4100. FX4100 may not be the fastest processor, but if you get that, and a decent board, the likelihood is that you will be able to do a bios flash when the next generation, Piledriver I think they are calling it, comes out, and possibly just a do a drop in upgrade to a better processor.