[svandamme]

i'de never build any business server with off the shelf parts... ever.
it's not worth the hassle, and half decent A brand servers can be found for 700 USD

if anything breaks, you'll have better result from warranty
faster replacement part sent, and you'll know it will fit the machine you need it for...

memory and Harddrives excluded, those can be found anywhere anyway
(do get decent ones.. not the consumer desktop models they are slower and have a lower MTBF, as well as a lower warranty
do get brand memory, viking or kingston not unknown crap),
but the chassis/and board...for a server, A brands are the best way
The cases will be better designed , better fans , airflow will be optimized, etc etc...i just wouldn't bother with anything else...

2 months ago i snatched 2 Dell R200 1 U rack servers in promotion for 300 euro a pop... dual core 2.2 ghz 6mb level 2 cache and 2 SATA disks
i rest my case.