Two systems I like depending on the trip:
Simple and Light but Bulky: Ridgerest deluxe trimmed to 15oz. This works well w/ my old Golite Gust pack which has enough volume to swallow the pad. Foolproof!
Heavy but Compact: Full length Z-Rest (14.4oz) plus BMW Torsolite (10.8oz). This works great with my Vapor Trail as the Torsolite rolls up inside very compactly, while the Z-Rest is a perfect fit on the pack's strap system. The Z-rest is also a backup in case of a Torsolite puncture.
Neither of these systems is super light weight, but they're both fuss-free and dependable for Winter. (Winter = 10-35 degrees in my neck of the woods.)
I've tried a Stephenson DAM (24oz) in the past and found it supremely warm and comfortable. But, it had a high fiddle factor, and I mistrusted it in case of puncture.
Inspired by Ryan's SUL challange, I'm tempted to try to go lighter this coming season with some combination of Gossamer Gear pads.
PS - Need some boots?