You could say i've finished building my low-power PC/Server.
All old machines have been virtualized and the new server is running fine.
These are the specs:
GigaByte GA-P35-DS4 motherboard
Intel Core 2 Duo E8200 2.66 GHz
8 GB RAM
Seasonic S12II-380 380 Watt 80+
2 * Seagate Barracuda 7200.10 250 GB
2 * Samsung Spinpoint HD103UJ
Matrox Millenium videocard
Additional RTL8139 NIC
OS: Windows Server 2008 Enterprise x64
Hyper-V with 5 VMs: 3 * Windows 2003 Server, 2 * Linux-based.
Avg power usage: 70W.
Here you can see how smooth these 5 VMs are running: