I recently setup an HP 6200 Pro Small Form Factor PC. It had 12GB of RAM and 2x 250GB 7200RPM disks running software RAID 1 on CentOS 6.
It was for a small office where the server was 10 years old and died. This beauty is dual core with hyperthreading! A perfect candidate to virtualize 3 Windows XP machines and a Linux file server. The printers are setup on the host operating system since they are specific to that site.
The virtualizations can easily be migrated from office to office or accessed over the VPN. Employees and IT no longer need to worry about physically moving their computer from one site to another. Data will remain in a safe location and backups can be made regularly by the administrator.
Some people may be interested to know that there is a parallel port adapter available from HP. It connects directly to a pin-out on the motherboard. I used it to connect a Panasonic KX-P3196. I had to install kmod-lp for my printer to be detected.
To run KVM you will need to enable VT-x in the BIOS. Go through every menu and you WILL find it. If this is not enabled the KVM module for your CPU will not load.
I also setup a Turnkey Linux Core as a central samba server which will backup nightly to Amazon S3.
Three Windows XP virtualizations get one logical processor each and 2GB of RAM. The Turnkey Linux Core server gets 1GB of RAM and one logical processor.
I will update this post if there are any problems with this setup.