Yeah Under armor is the shit as a base layer, like first layer between your skin and the cold, I use my NF fleeces as a mid layer, then if its really cold another fleece jacket of some sort before I top it all off with my wind/waterproof gore-tex Outdoor Research shell.
http://shift518.gom-host.com/showpost.php?p=263528&postcount=20
they keep multiplying worse then the PR