Beethoven,
There are also different conventions for shopping malls vs office buildings vs apartment/condo complexes vs hotels. The express elevators, for example, that kmar mentioned are usually office buildings, while sue and nan are more about apartments, and marcus addresses oddities in the numbering system.
I think, common-sense wise, that in the USA, we use Ground, Lobby, or 1 pretty much for the floor that is at gound-level. Then we continue with 2, 3, 4, etc, perhaps making allowances for mezzanines, balcony, or some other odd floor. The difference between USA numbering and British numbering is that the Brits do G, 1, 2, 3, etc. and we do G, 2, 3, 4, etc.
Mostly.
As Sue said, you can pretty much do whatever you want, and it sounds like Sydney's system would translate quite well to Metropolis so you would be safe numbering your floor as you are used to doing.
OK?
mmouse
