Here's a list of a system I put together for a friend of mine (in order of how I put it together)...
Coolermaster Centurion 534 Chassis
Coolermaster iGreen Power 500W Power Supply
Abit Fatal1ty FP-IN9 SLI Motherboard
Intel Core 2 Duo E6420 Processor
Coolermaster Hyper L3 Cooling
Corsair XMS2 TWIN2X2048-6400C4 Memory
Asus EN7950GT/HTDP/512M Graphics Card
Creative Soundblaster X-Fi XtremeMusic Sound Card
Hitachi Deskstar T7K500 500GB HD
Hitachi Deskstar T7K500 320GB HD
Lite-on LH-16D1P (Black) DVD-Rom (In Europe only)
Lite-on LH-20A1H (Black) DVD-RW
TEAC 3,5" Diskette Drive 1,44MB (Black) / 8 in 1 Cardreader (In Europe only)
Logitech G11 Gaming Keyboard
Razer Copperhead Tempest Blue Mouse
Logitech Z-4 Speakers (Don't ask why, he has 7.1 output)
Microsoft Windows Vista Home Premium (NL, 64-bit, OEM)
He got an overall score of 5.0 on his Windows Experience (3.0 and above being sufficient). More info here.
The whole list costs € 1496,77. Do the math!