saltywrote a review of SmartWool PhD Ski Graduated Compression Ultra Light Sock on April 2, 2013
These are my favorite socks I've had, although I have only had 2 pairs.
They're the thinnest you can go without sacrificing much if any warmth, so you get a really intimate feel with your boot (seriously - makes a difference).
The other major upside is the gradual compression, which is GREAT for my swollen ankle that I sprained playing football 8 years back - keeps that garbage in check.
Also, gotta love that blue!