$287
i7 950
$200
ASUS Sabertooth X58 mobo
$66
6GB G. Skill RAM 1600
$127
Corsair 60 GB SSD OS/Boot drive
$160 2X WD
1TB Black HD
$70
Lancool Case
$115
850W Corsair PSU
$640 2X
MSI GTX 570 OC
$50 Random Wireless card
$100 Keyboard + Mouse
$20 CM 212+ Heatsink
$20 DVD Drive
Total: ~$1850 before tax. With tax, it should be right around $2000!
Assuming your friend can't wait for the Sandy fix, I went with the i7-950/X58 generation. It's still a great performer and is a mature platform. Also, the SSD is expensive and I know you can switch with an OCZ Vertex 2, but apparently they're shipping a mix of the old (and better) 34nm Vertex 2's with the new (slower) 25nm drives with the same tag. It's like playing the lottery. For storage, your buddy can go with green drives if he wants, but I'm just playing it safe/giving you room for change. I'm also assuming he wants a gaming mouse/keyboard. I recommend the Razer Deathadder mouse and one of the Logitech G series keyboards, though mechanical keyboards seem to be the rage now. I also added a wireless card just in case. If he doesn't need one, I recommend allocating the money towards a better/larger SSD. I know 2 6950's will outperform 2 GTX 570's in 5760x1080 (8XAA) as well, but at least with Nvidia he will have the option of playing in 3D down the road. Again, no preferences or sides being taken.
Hope this helps. Feel free to make changes and ask for opinions!