This is one of those baselayers that will work everywhere, doing doing anything/everything. But especially while riding.
If you're always cold, or you know someone who doesn't have heated gear and could use a lightweight but warm layer that will fit flat and easy under any jacket, one of these windstopper vests might be a good choice.
Generally, if you can keep your core warm, it'll help keep the rest of your body warm too. I can handle riding during in chilly weather (like tonight, 48 degrees!) but it's the freezing cold air going down my chest that I can't stand. By simply shutting off this piece of the cold air, it makes the ride far more bearable.
You definitely can't go wrong with heated, but if that's too much or not an option (e.g. on a scooter or older motorcycle), one of these kinds of warm/windproof vests will be a huge improvement.
Above Right - North Face Women's Windwall Vest., $99
Above Left - Eddie Bauer MicroTherm Down Vest , $119 (this is even offered in regular/petite/tall sizing!)
