For summer use, I like these:

http://jas-townsend.com/product_info...roducts_id=238

They are as lightweight as you can get and still have a good-quality sock. The same company also offers a heavier long cotton sock:

http://jas-townsend.com/product_info...roducts_id=240

These have a good texture for kilt hose, but the quality isn't quite as good as the others: the pair I got had a heavy toe seam, which might be somewhat uncomfortable if your shoes are rather tight at the toe. Actually they might be good for people with wider feet -- my feet are somewhat narrow so these bunch up a bit at the toe, but it would probably be more comfortable if stretched out a bit more.

By the way, this company also has wool balmoral hats at the best price you will find anywhere:

http://jas-townsend.com/product_info...roducts_id=250

I got one of these too, and it is very good quality.

Cheers!