I've used these and love them:

http://www.honigs.com/detail.asp?Cat=1&Sub=93&Item=595

They're better than any black socks I've ever used.

Not sure about the Honigs ones...but I never thought that there was such a difference and how much more comfortable those socks are instead of plain old cotton...I'm sure there are other good brands as Ump25 is pointing out

The ones to which I referred in the Honig's link are quite comfortable, and I've worn my fair share of socks in my career.

I saw those and was wondering about those...but since I couldn't try them on, I didn't order them. Now I know that they are good socks.

Why does Honig's assume that umpires' shoe sizes all end at 12 1/2? They should carry big and tall sock sizes as well for those of us who have water skis for feet (size 14). I find that between my muscular calves and large feet, that the typical size 13 socks just don't fit. The 15-16, which is the big/tall size, are a much better option.