A few weeks ago when I was starting to do some Christmas shopping with a friend, I treated myself to this amazingingly warm and cozy sweater from Sirens!:
It is made with acrylic fabric (aka it's super warm stuff!) by a company called Parisian Collection. It is long and big enough that you can easily wear it over tights and it's perfect for the upcoming snowy / Christmas season! Sometimes, I find myself overheating in it so I know come next fall, it will serve as the perfect heavy sweater to wear outdoors on those chillier evenings, with maybe a pair of uggs or stylish boots.