Help me pick parts for Server!

[imported_Kensai]

This is what I've been looking at:

Tyan Thunder K8WE - 565$
AMD Opteron 275 - 1300$
Corsair 512MB DDR400 ECC Reg - 2 @ 145$ = 290$

Total = 2155$

 

[Slowlearner]

What is it going to do ?
Is a dedicated server needed at all?
How much downtime can you afford?
What server OSs are you considering?
How many clients will it have?

Without any info, any suggestions we make would be uninformed.