If you would have to create a data base for geomarketing applications yourself, what kind of datasets would you purchase/collect? The first goal would be to find new store locations. Another would be to assess the efficiency of advertising efforts in different areas.
Just a few off the top of my head
- street centerlines
- addresses points
- parcel polygons
- census demographic data
- existing business locations
- zoning polygons
- land use polygons
Demographics are probably the most important of your data sets in geomarketing. If you are planning on using the US Census/ACS (American Community Survey) be sure to research the proper methodology for using the rolling average that is the ACS. We no longer have a true snapshot now that the census long form is gone. Additionally, there are demographic data providers that create estimates on an annual, bi-annual, and quarterly basis if the Census data does not meet your needs.
Aerial photography. NAIP is widely available at decent resolutions for free.