To be honest, i don't think you can go wrong with just a simple therma rest z lite. It's dirt cheap ($25) and very light. I got one used and in perfectly good condition for $10. It's definately not as compact as today's inflatable pads but it doesn't have the problem with leakage because it's foam. I trimmed my z lite so that it goes from just my shoulder to my knee because those are the major pressure points against the ground that need to be padded. I just strap it to the outside of my pack. Works good for me.