I'm working on a construction web app that could benefit from storing geolocation information. When someone keys in a new construction site, they typically have an address or parcel that they enter. We have a couple of clients who use ESRI and have granted us access to their web service in order to pull layer info based on address/parcel. I've been thinking though that it may be useful to also store the geolocation so that we can graphically display a map with pins indicating project locations. We would probably use Google maps for this portion since we don't have a license to use ESRI ourselves. Being new to GIS im a bit confused on how to best store this geolocation in the database in order to be as flexible as possible. Should i store a lat/lon or a x,y coordinate with a spacial reference? Is any spacial reference more globally adopted than another or does that even matter? My goal is to store the most readily usable format for use in multiple systems.