For my job I have to make sure that my PPE (personal protective equipment) is as good as it can be, the fit and the functionality. I choose my kit to help me stay as warm and as dry as possible, very difficult when we live in a warm, wet, martime climate; as the last months worth of weather has shown.
I try and use the best that's available and most of this mimics some of the worlds most adapted animals for their environments. Outdoor kit has come on leaps since the token woolly jumper
Here are two articles by leading scientists gear and outdoors people. Taken from UKC one of the website dedicated to the outdoors and its supporters.
Part 1 http://www.ukclimbing.com/articles/page.php?id=5105
Part 2 http://www.ukclimbing.com/articles/page.php?id=5163
As an enjoyable addition to these have a look at http://innovation-for-extremes.net/gear-timezone/
Enjoy the articles and have a look at your wardrobe and see if its fit for purpose.Then come out on the hills and try some of it out.