Smartwool Men's PhD socks
I have used this model for about two years with running shoes. They are lightweight and very comfortable. They breathe very well as they are wool and this really helps to keep your feet cool and dry. The only issue is that they tend to wear out in the heel and forefoot areas faster than other socks. Since they tend to cost more than other socks this may be an issue for some, but I still buy them as they work best for me.

Hooked on it!
I bought this sock for myself just to try them out, and after a week of using them, i ended up buying more for my self and family. They are comfortable, no irritation, really warm, and no smell after long hikes. Now this sock is my go to sock. Plus the customer survice with Altrec are super nice.

Nice lightweight sock
Just a standard light weight wool running sock! I would recommend that you spend a small amount more and get the PhD Outdoor Ultralight or Light sock which seems more versatile in its construction. I have no complaints. These socks are comfy and have withstood many washes without significant evidence of wear.

Light Weight
I recently purchased these socks for a trip in the Smokey's. I will say they are comfortable and very light. However, they are not thick enough to protect your feet and toes from blisters as I discovered. Since I was hiking an average of 15 mile days while out there these socks did not have the durablility and thickness I needed. For a shorter distance hike or even a day hike they are perfect.

Great fit
I love smartwool. The fabrics are wicking and do not get that sports smell. However the sizing is a bit strange. These are mediums and fit very well but are officially outside my size.