I suppose it depends on what your goals are; despite being officially metric, my Canadian and British friends still seem to exhibit a melange of imperial and metric in everyday life.
I notice sometimes when watching British television that stones are commonly used as a unit of weight, which is interesting because it's imperial, not metric, but I've seen never it used in American contexts.
But the time thing goes to show the absurdity of people's frame of reference. The same people that judgingly ask why the US hasn't gone full metric will say how absurd the idea of base 10 time is.
