An update on my old home server since I just upgraded its storage, RAM, and it no longer lives in a cardboard box.
OS: Debian Stable
CPU: 4x Opteron 8431 2.4GHz hexacores
Motherboard: Supermicro H8QME-2+
Memory: 32GB (16x 2GB) DDR2-667 ECC Registered
PSU: Corsair CX750M
OS HDD: Old WD 160GB laptop hard drive
Storage: 2x Toshiba 5TB in a ZFS mirror
and 2x Samsung F3 1TB in a ZFS mirror (probably retiring these soon)
Cooling: 4x Cooler Master Hyper TX-3
I use it...