Depends on the day. When its spring, I will wear a tshirt or polo under a shell, with boxers and shorts over those. During the cold part of the year, I use either a Patagonia or DNA longsleeve synthetic top, with either Patagonia R2 insulation or a down vest under my shell and use Patagonia long johns to keep my legs warm under my pants that are lightly insulated. Year round I use smartwool socks, the best ones I have found yet.