@justin258: Maybe I'm just personally overly pedantic, but I'm a northerner (from Connecticut, though I've lived in New Mexico for the past ten years), and -- at least where I'm from -- we don't call every sled a "toboggan"; we reserve that term for traditional examples of a toboggan. Everything else we just call a sled.
Also, according to The Internet, the term "toboggan" in reference to the hat started as shorthand for "toboggan hat", ie "a hat suitable for wearing while tobogganing." Kind of weird that the shorthand for the hat stuck, yet people stopped using the term for the sled after which the hat takes its name.
Anyway, I've always just called it a knit cap or "winter hat." Disappointed that option wasn't in the poll.
Most of the differences stem from the fact that this type of cap goes back centuries, with several different origins, all influenced by original purpose and the language spoken at the time in a given area. They're all more or less referring to the same thing, though, and are all equally legitimate. Although I maintain calling them "toboggans" as shorthand for "toboggan hats" is needlessly confusing. What if people started using "baseballs" as shorthand for "baseball caps"? Madness.