neither do we. i was surprised the first time i heard someone mention that Canadians are best known for saying that, above all else. that was MANY years ago, of course. sometimes i just listen to people talk so i can note if or how often they actually do say eh....some people (my oldest daughter included) say it a ton of times in one conversation. i have no idea where it originated from.
eh? toques, beavers, moose, mounties and beer. we're known for all the best stuff. oh yeah, and snow.