zipper on outsideI find having the zipper on the outside very useful. When I want to cool down after coming into a hot lodge, I can unzip both outsides; either from the top down, or the bottom up. This helps prevent me from overheating. The zipper also works well when suiting up in the AM. Sometimes I sweat when I am booting up, and being able to open the pant legs helps keep me cool. Be sure to get a zipper that is water and wind proof. Most just have a fly to cover the zipper. That fly gets in the way when you try to close the zipper. Xeterra pants have no fly, but they do keep out the water and wind.
Also I didn't mention it in the first post, but spend the extra to get Gortex or fabric with similar properties. Some fabrics are coated and they do not last like Gortex. gordo