Gigabyte X58A-UD3R (USb3.0, SATA III )
Kingston DDR3 1600mhz tri-channel kit 3x2GB
2TB WD HDD
Gigabyte GTX470 superOC 1248MB
Probably a little overkill for strategy games.
Even a Phenom II X4, 4GB DDR3 Ram, GTX 460 and a 1TB hard drive would do. That also cuts the cost ALOT.