The latest version of one of the most popular midweight synthetic baselayers of all time.  Patagonia Capilene®.  This fabric layers easier, wicks better, and drys faster. The outside of the fabric feels soft and smooth, and makes layering easier.  A diamond grid pattern on the inside provides next-to-skin comfort and increases the warmth, breathability, and moisture wicking ability.  If you are looking for one baselayer to serve the vast majority of your outdoor and indoor needs, then this is an excellent choice.