Trying to build a gaming PC under $500

This build won't work. The motherboard you have chosen only supports up to 95W CPUs. You are better off going with this board

ASRock 960GM
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157323

as it supports 125W CPUs and will allow you to use AM3+ CPUs latter on. As for high/Very high you won't hit that with more demanding games using that video card, but might be able to on older or less demanding games.