Just my 2 cents.
If is going to be a server, most likely it is going to be on 24x7.
don't use cheap parts the downtime is going to cost you more money later on.
I would suggest either Tyan or Asus's motherboard
with a large HS, in case the the fan die. If you can somehow redirect another fan to H/S that will be added protection.
1 Gig Ethernet Port for quick I/O.
If you have higher budget, Don't use IDE HDD, I got many IDE failed after 12 months 24x7
SCSI is much better on server.