What Americans call Smarties, we in Canada (in Alberta anyway) call Rockets. We seldom see them in stores unless it's around Halloween time.
Personally I didn't care for peanut Butter Twix but I LOVE peanut butter Snickers. Also we can also get several kinds of M&Ms...almond, peanut, plain, pretzel, peanut butter, dark chocolate or coconut are all available here, as well as regular and mint Aero. We also have Big Turk and Three Musketeer bars, (neither of which I personally care for, but to each their own) I'm also a huge fan of Bounty, which is coconut covered in dark chocolate.