Luckily, we have five 3U rack mountable machines in barely used condition. I'm planning to upgrade 3 of them to provide the database server, archive server and web server. Out of the box, these machines have Quad Core Xeon 3220 processors on SuperMicro PDMSA+ motherboards (including Intel onboard RAID) with 460W power supply, 4GB ram, a single 80GB SATA drive and DVD-ROM drive. These servers will be managed remotely via TightVNC, but in the event we need to hook up a monitor, there is onboard video.
For the web server, I'm going to up the hard drive to a 250GB plain vanilla SATA unit and leave all other hardware as-is. Operating system will be Windows Web Server 2008.
For the database server, I'm going to take 4 of the 80GB SATA drives and create a RAID 5 array (striped with parity) for 240GB of storage. I will replace the four 1GB memory sticks with 2GB sticks (533MHz DDR2) which brings the motherboard to its maximum of 8GB. Operating system will be Windows Server 2008 Standard.
For the archive server, I'll add an Adaptec 5405 SAS hardware RAID card. This will be married with four 450GB Seagate Cheetah 15k.6 SAS drives in a RAID 5 array, for 1.3TB of storage. Operating system will be Windows Server 2008 Standard.
Total cost: about $4700.
Sound like a reasonable plan?