I'll try and fill this out with the specs of the 'high' and 'low' end rigs that I am currently using.
High
Dedicated folding rig or part time -Part Time
Brand/Model/MHz of CPU(s) - 2 x Intel Xeon X5650 @ 2.67Ghz (6 Cores plus HT)
Brand/Model/Mhz of GPU(s) - None
Brand/Model of Motherboard(s) - Dell Own
Brand/Model of PSU - Dell Own
Case & Any Mods Done - Dell R410 1u Rack mount server
The Rig's approximate PPD - 30000
Operating system/Driver version(s) Used - Windows 2008 Server Standard Edition
Virtual or Native SMP(s) - Native
Low
Dedicated folding rig or part time -Part Time
Brand/Model/MHz of CPU(s) - 1x Intel Xeon E5630 @ 2.53Ghz (4 Cores plus HT)
Brand/Model/Mhz of GPU(s) - None
Brand/Model of Motherboard(s) - Dell Own
Brand/Model of PSU - Dell Own
Case & Any Mods Done - Dell R410 1u Rack mount server
The Rig's approximate PPD - 8000-9000
Operating system/Driver version(s) Used - Windows 2003 Server Standard Edition
Virtual or Native SMP(s) - Native
All of these servers below are folding plus another couple dotted around