I use an older Thermarest Ultralite, 3/4 length, on top of a closed cell pad (older Mt. Washington egg-crate style EVA foam). This gives me a closed cell pad for sitting on and basic insulation, with the t-rest for added insulation and comfort. If the t-rest goes bad I still have something. I'd be reluctant to go with only an inflatable pad on the snow, especially for longer trips.