Who uses the metric system, anyways?

Russia uses the metric system, apparently, and France I think. Fortunately, I studied physics at university and have used the metric system before (I don't think I've used it since). I can never remember the metric/English conversions, though. This has caused no small amount of confusion to my Russian friends when I tell them about America. "Yeah, a hot summer day in New England can get up to 200 degrees C, sometimes" or "The speed limit on the highway is usually 500 km/h, but most people drive faster." Good stuff.