I like the Thermarest Neoairs, on top of a ridge rest. The Neoairs pack down really small, on the order of a 1-liter Nalgene bottle. The ridgerest doesn't but it can ride outside the pack, on the side or underneath. Underneath is good in that it protects the bottom of your pack when you sit down.
+1
I like the Thermarest NoeAir best for backpacking. I also own a RidgeRest. However, most of the time I carry a cheap closed cell foam mat in lieu of the Ridge Rest. The closed cell foam pad is so cheap that I don't mind if it gets damaged on the outside of my pack. But I would hate to destroy a $40 RidgeRest.
You have to blow up a NeoAir and that takes about 15-20 minutes. There are several self inflating pads that look interesting and the Thermarest Trail Pro is one example. But all of them weigh about twice as much as a NeoAir. Self inflating pads aren't really self inflating but they fill up in less than half the time of a true air mattress.
KC
