Latitude and Longitude could be exclusionary to those that don't want to be zeroed in on.

If the field format is agreed upon, and it is flexible, we are in business

I propose this: 3-letter country code, 2 letter state code, and 5 digit zip). That way, the field can be broken down by varying degrees, and people can input the level of detail that they are comfortable with.

E.g. USAMA02126

This lacks flexibility (very United.S(c)entric, though, b/c I am unsure how state and zip codes would apply to the rest of the world.

Update: I agree that Longitude/Latitude seem like a much better idea as long as the trailing zeros are an option.

-OzzyOsbourne