If you are Ocing with AMD, use a DFI board. They are the best. The voltage regulators are smart, among other things.
As far as liquid nitorgen goes.... ouch. I've seen it too. You need special cylindars to use it, and it is rather difficult to get your hands on. I would use it myself, but it has significant life-ending qualities to it, and I, personally, want to stay alive so I dont feel like messing with it.