My standard, canned answer to this question would always be a skirt. I've worn them daily for the last six years. I wear a tie to work and always come home and immediately change into one. I have two for yard work and three for house wear. Sadly, I have not ventured out as dressed.
I say this is always my most comfortable, but today I took delivery of a long sleeve nightgown type sleep shirt in my size made from bamboo viscous and rayon. It's omg comfortable. Yesterday I gave myself a full body IPL and my skin is sooo smooth that this thing feels wonderful. From longevity, I will say my skirts, but this new nightgown is wonderful.