Get an ATI.Nvidia's 400 series, like raybob said are way expensive.A 5770/5870 will easily outpower the GTX 460.Good thing you picked a Phenom,Athlon X4's still don't have the power as the Phenom's, they may clock better but they suck.And DON'T get a ASUS mobo, they blow.If they fuck up, you can say goodbye to fixing it, or getting answers from ASUS's tech support.Get a Gigabyte one, much better and cheaper for the stuff you need.I'm guessing that you picked DDR3 RAM, since the ASUS Crosshair IV only supports DDR3.So, this mobo is way cheaper,and will give you what you need.
EDIT: or this one.(if you're looking for a newer chipset)