Socks for what?
I find bulky thick wool socks suit almost all situations and can be worn for days, and are very comfortable. My feet do not sweat much though.
I have tried Icebreaker, and the cheap eBay ones are just as effective, though a little hotter they are more durable.
These look exactly like what I bought a couple years back. Just bought a couple more pair.
I have couple pairs of Ininji toe socks, and they are great too, especially if you think you might get into a situation where your toes cop a pounding (wet for extended periods).
For really cold/wet situations I added a pair of Sealskinz to my kit at the recommendation of others (think snow/canyoning) on here. I cannot recommend them yet. I have heard of problems with bunching under the arch, as they are very thick.