I have been wearing Merino wools socks in the winter for several years now and love them.  They are thick, warm and dry.  I ride a motorcycle for fun, especially on long trips and found that many of my fellow riders wear wool even in the summer.  So I did some research and apparently Merino wool is some kind of miracle fabric. Ok, maybe that is a little much, but it is suppose to keep you warm in the winter, cool in the summer and dry all of the time.

I can say that my feet never get cold in the winter with them and now that I have been wearing these socks with my Goretex Merrell tennis shoes in 95+ degree, humid weather my feet don't get hot either.  I can take my shoes off at the end of the day and my feet are dry.  I also don't seem to get the hot spots on the bottom of my feet that indicate a blister could form because they are staying drier.

These socks are comfortable the minute you put them on.  They have just enough padding where its needed and elastic to keep the sock up.  I may be premature rating them now as I can't speak for durability yet, but they are comfortable and do live up to the promise of Merino wool.

*** 2012/08/22 Edited ***
I have worn the socks on multiple occasions now and my initial thoughts on them still stand.  I am very pleased with these socks and plan to get more merino wool socks to cover all situations.