180s-style earmuffs are fairly professional looking and keep your ears and head very warm -- that is, as long as you don't mind the top of your head getting cold. The ears are really the most important, though.
On the hat front -- a while back, Mike's mom hand knit a few hats that the store sold. I don't know if they ever made it online, but they were awesome. If I were a hat-wearing sort, I definitely would have picked one up.