Well the E6750 or E6850 CPU would be fine, but if you want to 'spend' the money then the Q6700 or QX6850.
A single 8800 GTX is good enough for graphics, but if you want to 'spend' the money then the 8800 Ultra or Dual 8800 GTX/Ultra's.
700W supply should be fine, but again if you want to 'spend' the money then the 1000W.
2GB of RAM should be fine, but if you want to 'spend' the money then the 4GB's. Not sure what brand they are using for their "Extreme-Performance 800" memory, but it will cost you an extra $475 when it can be had for much less than that.
Everything else comes down to personal choice. HDD space, DVD drive peripherals ect.