Hi!
I still say build it! You have warranties on every single hardware anyway.
And go i7, for the sake of (as usual in the gaming pc world) a relatively good future proofing.
This should make a really nice rig:
Case:
http://www.newegg.com/Product/Produc...82E16811119194
With plenty of room, 2 x 200mm + 1 x 120mm fans, this case can probably also chill the beer while gaming.
Psu:
http://www.newegg.com/Product/Produc...82E16817139011
Modular psu. Less cable clutter and improved airflow.
Mobo:
http://www.newegg.com/Product/Produc...82E16813188049
cpu:
http://www.newegg.com/Product/Produc...82E16819115211
Cpu cooler:
http://www.newegg.com/Product/Produc...82E16835608007
With some overclocking done with this cooler.. The i 950 cpu will be able to do 4 GHz without getting too hot.
RAM:
http://www.newegg.com/Product/Produc...82E16820104091
Video cards:
http://www.newegg.com/Product/Produc...82E16814127429
The Intel i7 mobo's supports both SLI and crossfire.
Hdd:
http://www.newegg.com/Product/Produc...82E16822136320
Backup hdd:
http://www.newegg.com/Product/Produc...82E16822148346
DVD burner:
http://www.newegg.com/Product/Produc...82E16827151187
Total of: 1951.44$ No in mail rebates counted for.
If he stilll wants a prebuild?
Stay clear of HP, Compaq, Dell, Gateway and other "office machines". And Alienware + Woodoo. The latter 2, is way too exspensive for the stuff you get and have lousy customer support.
I say this should be a good prebuild:
http://www.newegg.com/Product/Produc...82E16883227155
Wanna speed up things even more? Get another GTX 285. The CoolerMaster HAF, is a nice case. Comes with a pretty good 800W psu.
But building the rig abouve will still be better and cheaper.