When I'm formally dressed and it's not too hot, I wear a top hat. I even bought a pack of small craft feathers so that I can match the feather to my shirt or tie. It looks awesome with my greatcoat. I used to have an
Ushanka, which worked great for when it was really cold and I was wearing my army surplus trenchcoat, but that got lost.
I do wish I could find a good fedora that fit (Indiana Jones rules). Heck, even a trilby or cowboy hat would be something I'd wear occasionally.