Let me give you the current configuration we have in mind, one with the single processor, and one with dual processors.
1. Intel Xeon X5680 3.33 Ghz 12M Cache, Turbo, Ht, 1333Mhz Max Mem
6GB Memory 1333Mhz Single Ranked UDimm for 1 Processor (Is it worth it to upgrade to 12Gb of ram?)
PERC H700 Integrated Raid Controller 512Mb Cache
RAID 1 for SAS 6/iR, PERC6/i, H200, or H700 Cntrl (Non-Mixed Drives)
2 X 600Gb 15k RPM Serial-Attach SCSI 6Gbps 3.5in Hotplug Hard Drive (Would it be worth it to get another drive and go to Raid 2, 3, 4, or 5?)
Embedded Broadcom, GB Ethernet NICS with TOE
2. 2 X Intel Xeon E5640 2.66Ghz, 12M Cache, Turbo, HT, 1066Mhz Max Mem
12Gb Memory 1333Mhz Single Ranked UDimm for 2 Processor
PERC H700 Integrated Raid Controller 512Mb Cache
RAID 1 for SAS 6/iR, PERC6/i, H200, or H700 Cntrl (Non-Mixed Drives)
2 X 600Gb 15k RPM Serial-Attach SCSI 6Gbps 3.5in Hotplug Hard Drive (Would it be worth it to get another drive and go to Raid 2, 3, 4, or 5?)
Embedded Broadcom, GB Ethernet NICS with TOE
Realistically the most users we would probably ever have on the server at a time would be 15, maybe 20. It's a small network and both of these configurations are probably overkill but we want to get something that will last a few years. I am very new to server setups as i am sure you can tell so any advice or help would be much appreciated. Thanks.