Book Sock Yarn?

Does anyone have an recommendations for a good thick boot sock yarn? It is for my SO, so it has to be in man friendly "colors", where colors is code for not really a color unless it in subdued earth tones. Nothing self stiping, although something space dyed may be ok. Good yardage for man-feet is good (though I can buy extra if I need to).

Hand wash is fine, but I really need there to be some nylon/tencel/non-wool content because really gets some mileage on each pair (haha, originally that was unintentional, but it is funny enough to leave). A 6-ply would be good, but it definately should be of sport or dk weight.