Just finished these rainbow socks, using "Felici" yarn from KnitPicks, in their "rainbow" color.
Although advertised as a fingering weight yarn, it felt a little lighter and seemed to be much thinner than the yarns that I usually use. So I used smaller needles than usual; and then spent almost twice as long as I would normally take to make socks! The most time consuming part was the 1x1 ribbing for the cuff.
They were knitted top down using two circular needles, size US 00, 92 stitches per round.