It’s winter so I have to say my favorite piece in the winter is whatever icebreaker or smart wool base layer I wear. Icebreaker is too expensive so I try to find sales (which are very rare) and I buy one piece per year. Over the years I have collected a great set of icebreaker pieces. I highly recommend icebreaker for it’s wicking and warming properties and it does not stink so technically you can wear it for a long time before washing! Ewwww. You can though.