What kind of games...with that price range you won't be able to play games like skyrim or battlefield on ultra...you would need $500 almost just between the CPU and GPU, for good gaming.
light gaming, I don't do much of it. I have wanted to try Entropia, but if it requires stuff out of my league then that is fine. I mainly just want more capability to possibly get started in PC gaming. (Xbox Player)
My main concern is being able to have dual monitors and be able to play high definition movies very smoothly.
I just tried to find you parts within your price range that could roughly match an xbox 360's graphics and I just couldn't do it within your price range. I got to about 525 dollars and that was without a video card.
I would still reccomend saving a couple hundred more dollars.