Bear in mind, the US actually uses both systems. (And both are taught in school - at least I was, and I'm 30)
For instance, I was just recently drinking from a 2-liter bottle of soda. Pill dosage is given in milligrams, not grains.
Personally, I like using the Imperial system better. It's actually easier for everyday life, at least me, because my foot is exactly a foot long.
Also, the metric system is flawed. People use mass instead of the proper unit for weight. While there is a corelation, it's very easy to weigh something, but not so easy to figure out somethings mass (since most scales are dependent on gravity to work, and the Earth's gravity varies a tiny bit).
Also - the celsius system sucks for anything other than boiling water. Even in science, you have to convert it to Kelvin. While the F scale is based on the common extremes you experence on Earth - where I live, it gets to be around 100 degrees in summer, and 0 in winter. Much better for weather reports than 38 degrees and -10 or so.