Another vote for both with a slight caveat. It is my only moving top for most 3 season conditions other than a synth or merino t-shirt and it is an older highly breathable houdini. I don't take a long sleeve hiking shirt, a light fleece(until shoulder season), or a long sleeve baselayer. Sometimes folks who don't like wind shirts have one or more of these with them which when combined with a rain shell meet all of the same needs(for some people and conditions even better). I really consider my windshirt to be a hooded trekking shirt. I have even layered it under a rain shell successfully.