we use single CPU processors. Singel CPU is enough if you only server static files, anmd dont have more than 500.000 daily hits
1U server:
CPU Intel Pentium 4, 2,6GHz, FSB 800MHz
RAM 2 x 512 MB DUAL DDR 400MHZ
IDE IF 2 x 80GB SATA150 7200rpm 8MB cache, raid 1
NIC 2 x Intel on-board 10/100/1000Mbit
VGA ATI range on-board 8MB PCI
USB 2 x 2.0/1.1
CD rom black 52x speed
Floppy black 1,44
$1400
or if you need more space:
IBM x235 Xeon
P12AXFR
8671-2AX
2.0Ghx Xeon
512MB Ram
NO disk
Link
http://www-132.ibm.com/webapp/wcs/st...-840&langId=-1
$1500