I wear a big old bobbly zip-up fleece all the time. It's so practical - baggy so it fits over everything, I can put layers underneath it when it's cold, it's comfy and soft and easy to move in, it has big zip pockets that I can fit loads into, it zips right up to my chin to keep my neck warm, I can screw it up and put it in a backpack, I can chuck it in the washing machine whenever.
Problem is that it's deeply unfashionable. Are there any other light jackets out there that are just as comfy and practical, but lots more stylish?