You all know that Mike C! is an advocate of "thinny-thin" socks. The new minimal shoes (not the toe-y ones) also do well with really thin socks. And if you're fording many streams, really thin socks help things dry quickly.
I haven't seen it posted anywhere, but cycling socks are great "thinny-thin" socks. Most are made of nylon, although wool is available (not quite as thin). The nylon ones come in a huge assortment of designs, colors and heights.
Just as an example of what's out there, here's a link to 8 pages of men's cycling socks:
http://www.sockguy.com/Category/9_1/Socks.aspx
(I have no connection with the company)
Cycling socks are widely available at cycling shops, and can often be found on sale on the web. And the nylon ones last forever!
Cheers!

