Let's introduce my nice server to you all:
Mainboard: Asus P5Q (energy safer !)
Powersupply: Coolermaster RS-460 (energy safer, low noise)
CPU: Intel Celeron 440 2Ghz (64bits) with default Intel cooler
DVD-player: LG DVD/RW drive
Videocard: simple PCI-X card with passive cooling
Memory: 2x 2GB Kingston EnergyX (plate-cooling)
Harddisks: 5x 1TB SATA, 1x 500GB IDE
Harddisk-enclosure: 1x ICY DOCK MB672SKGF Sata with LCD
Case: 4U servercase with big coolerfan (inserted in a TOTEN 32U server cabinet, oversized but I use it for other stuff too.
DATA MIRROR-1: used for all our own storage at home
2x 1TB SATA harddisks + 1x 1TB SATA harddisk in Sata enclosure
DATA MIRROR-2: used as external backup storage for our clients
2x 1TB SATA harddisks
System disk
1x IDE 500GB harddisk: in use for the server operating system
Installed software
OpenMediaVault (latest version ofcourse)
Webmin
(used software in the past: ClearOS (Clarkconnect), Ebox, HDA, Suse Linux, Openfiler)
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On a regulair basis I change the harddisk fitted in the enclosure for another harddisk, the old one is stored on another place as backup.
I ordered an another enclosure for mirror-2, will be added soon.
When you use software-mirrors, it's very easy to create a new harddisk-mirror with just one backup-disk 
I use Webmin for it, but it seems to be OpenMediaVault could do the trick too.
The mainboard and CPU are not the fastest, but it's fast enough for data-storage, and some Virtualisation of one virtual Windows system.
Focus was: energy saving !!! And this server doesn't use a lot.
Ok guys, show your server too !! (just for fun)