Jim, and Guido Brother, and others who are thinking one system of units or the other is easier: it can all be easier if you carry a calculator with lots of memories-- just save any constants that will be handy and they're at your fingertips. I'm partial to metric also, but I need to deal with both systems for most courses I measure.
I'm going to start another thread on this (calculators) when I get around to it.
Meanwhile I'm a little curious: Guidos, aren't 5 places after the decimal enough? And Jim, why would you want to deal with yards, feet and inches in any case? (Other than giving feet or yards when describing locations)