Is it fair to say then MapPoint + Laptop + gps receiver = a fully "active" gps system.
Yep, that's exactly what you will have.
What I'm trying to describe is a parellel setup to say purchasing TomTom, Garmin, etc?
If you're referring to things like the Garmin Nuvi models or TomTom One, etc. you will have so much more.
You will have the realtime nav functions. Plus, you will have superior trip planning if you want to do complex multiday and/or multipoint trip routes.
You would get all that with Streets&Trips.
you get all that plus
integration with Microsoft Office and an API.
How good is that?!