Western Mountaineering 20 degree Alpenlite = Awesome!
I am sleeping on the Montbell U.L. spiral hugger #1 and NeoAir pad. My system weighs just under 3 pounds and is rated to 15 degrees. It is very compressable and I love it.
My partner is on a BA blackburn with insulated core pad and he loves it. I believe his weighs about 1.5 pounds more than my system but is rated for colder weather.