bwpearre2340835 wrote an answer about Therm-a-Rest 40th Anniversary Edition Fast and Light Sleeping Pad on May 28, 2012
Me too. I've found that the self-inflating pads just aren't thick enough--not enough give in the middle. Even the thickest don't do it for me. The Exped DownMat (even the 7cm one) was a revelation for me. Not quite as comfortable but still adequate in the summer (and much lighter than the DownMat) is the NeoAir.
Also, I've found that it's very worthwhile carrying a pillow. I use the Cocoon inflatable one that weighs 70 grams, but it's not very warm in winter, and I haven't found a solution to that problem yet. It'd work okay to put between your knees to relieve back strain while you sleep, but something wider such as a sit-pad might work better for that.