In the UK we use a mixture of both. Schools are usually taught in metric, and the temperature is metric, with every weather forecast using centigrade as opposed to Fahrenheit. But most things are still in imperial, roadsigns use miles, milk is in pints, weight is in stones and pounds, height is in feet, so most everyday things use imperial measurements. For example, I have no idea how long a kilometre is, how much I weight in kilograms or how tall I am in metres, but I know how long a mile is, how much I weight in stones and pounds, and how tall I am in feet.