[OpenLayers-Users] Recommendations for Map data?

[Arnie Shore]

Folks, I'm looking at porting  an application now using Google's maps 
and API to a platform that has no reliance on Internet availability.

It's Open Source, and OpenLayers is the API of clear choice.  Given that 
as half of the solution, what's recommended for the other half, the map 
data?  I'm looking for suggestions that meet the following criteria.  
Users cd be anyplace, so I'll need something that wd cover the US, be 
moderate in price, and readily used with OpenLayers.  GMaps-level of 
resolution and functionality is a target.

There's several CDROM's around, notably those fm Microsoft, but I'll 
appreciate any suggestions.  Thanks,

Arnie Shore
Annapolis, MD