[K12OSN] Server specs

[Ken Johnson]

Operating on a limited budget, I am seeking a server on EBay to
support 10 users, on a K12LTSP network that will grow in the future.

I need to get the most bang for my limited buck.

I have seen some Dell Poweredge servers and some Compaq Proliants.

Which is better for K12LTSP? 

Are there any 'gotchas" with either Dell or Compaq?

Does either have any special power requirements?

I want to start with about 2 Gig of RAM and SCSI drives.

Which is more important -  processor speed or RAM ? 

Would a 500-800 Mhz processor feel fast enough?

What about RAID - is that something I should be looking for?

Should I look for additional SCSI drives on EBay or seek new ones?

Thanks in advance.