Microsoft MapPoint that's a lot like Streets & Trips, with additional features — it includes interfaces to programmatically control it, plus an embeddable ActiveX control.
In Streets & Trips 2004, and MapPoint 2004, Microsoft added GPS support. You can easily configure it such that the map tracks your current position as reported by the GPS. You can also configure it such that your view of the map is rotated such that your direction of travel is always up. Quite convenient for in-car navigation.
Jim Lyon, unfortunately, search as I might, I could find absolutely no mention of the GPS features in the programming interface documentation. “Drat!” says I to myself. “The GPS features probably came in too late for the programming interface people to catch up.” I was disappointed, but I understand how these things can happen.