Here are my three for 2011:
Definitely the most used this winter, because I wear it around home too: A Katerina Pierini knit hat, in merino wool. Her hats are works of art and warm, too!
A KookaBay custom Climashield insulated air mat. It is 20"x 60" x 3.5", mummy style, insulated to R5, weighs 12.9 oz. It has taken me a long time to get used to it, particularly the narrow bottom end. I've also had difficulty keeping non-skld stripes on the bottom; they promptly peel off (see below for the solution). Even so, it is by far the most comfortable pad I've ever had. After reading about the problems with the Peak Elite AC (which I'd originally had in mind), I'm sure glad I went with KookaBay!
Just bought, so I've not had a chance to seam seal or try it outdoors: ZPacks Hexamid Twin, the version with screening, plus their twin size bathtub floor ground sheet. I set it up in my living room, got my sleeping bag and pad and my dog's sleeping pad and the two of us got inside. Next thing I knew, it was 4 hours later and we'd both had a nice nap! There's lots of room (including headroom) for the dog and me, and I'll even be able to add one grandchild, although that will be a bit snug. The cuben floor is far less slippery than silnylon, so my KookaBay pad stays put! I carefully checked out the dimensions and headroom, because my past experiences with side-opening tents were not good. There's lots of space over my head in the Hex Twin, with no danger of brushing my head or feet against wet tent. Note: Just to be sure, I'm keeping my prior tent (GG/Tarptent Squall Classic) until I've used the Hexamid Twin for a season. One or the other will be for sale next November! Yes, expensive, but about 3/4 pound savings. As I get older, this amount of weight savings becomes more and more significant.