i have used under armour in the past. at first, i thought they were great. but, if you are on a back country trip that last a couple of days, they do stink. what i have found to work is anything with x-static or similar silver technology. i can wear the same top and bottom baselayers for 3-4 days straight, hunting all day without stinkn'. for the money, that has been great for me.

cabelas has them. heres the link