Sometimes I'll just walk through the yarn store and a certain yarn jumps out at me. This was the case with this yarn. Of course, I'm sure thousands of people have had this exact experience with this same yarn, but hey. What can I say? These people know how to make good yarn.
Madelinetosh Tosh Merino Light, in colorway Byzantine, which (by the way) is still available. This beautiful single ply yarn is just a pleasure to work with. I'll be a Madelinetosh test knitter any day. The color changes are subtle, but unpredictable, and it doesn't pool into unsightly colors. One skein made this: