Hi,
from what I found out:
WGS84 is the 'map datum'. Dat means every latitude/longitude will bring you to a certain location. Using NAD27 would give a different location for the same coordinate! WGS84 is what GPS uses, but you can change that often to match map's 'datum'.
The presentation layer can be UTM (translation to XY in meters per map cell), or the degree thing (always latitude first, then longitude). Common in mapping was: degrees°minutes'seconds" but computers can't cope with that easily and users don't know how to enter that. Also with degrees°minutes.fractionminutes'.
I would suggest to use degrees in the hddd.ddddd format: 52.52121 degrees is (vertically) 1.11 meters per 0.00001 degree. Horizontally (Greenwich Meridian distance) it depends on the latitude, but 'here' in Amsterdam/London every 0.00001 degree is 0.68 meters.
I would say: WGS84 and hddd.ddddd is the right standard. A pity that Google start up in some other presentation. Tools->Options->set to degrees to make life easier.
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