Terrestial Mapping software/application?

I'm looking for a GPS that has a street mapping application that would allow me to add various graphic objects at a specific Lat/Lon via a USB or through RS232 serial. AVMAP comes close, but is way expensive, and the base map detail sucks.

Alternatively, I would like to get a street-level base-map application running on a Laptop which has an external GPS (to center the map at my current position, possibly rotate the map to heading-up), and has an API interface where various graphic objects can be superimposed on the base map by software calls with the Lat/Lon.

Any one have a solution?

I would just write a Windows app showing a map (a scan of a local streetpmap would suffice) and referenced to the GPS coords. Once the map is onscreen you can draw icons etc to it as windows images, or draw text directly on top.

Sorry I don't know a ready made solution but someone with any proficiency in Visual Basic etc could easily write code to show a map onscreen and draw some icons on it. Maybe you could find a student to code up an app for you?