If you want a good navigation application to be used on a laptop, Microsoft's Streets & Trips is the way to go. I've tried Delorme's offering and I can tell you that it is over complicated and the user interface is not at all intuitive.
If, however you fancy yourself stepping up into a PDA (with a GPS antenna option), I highly recommend "iGuidance". At around $100, the application is more expensive, but reasonable where PDA navigation software is concerned. It also comes with a client that will run on a laptop. Navigation software is only as good as the map data and iGuidance uses data from NavTek (sp), known for the most accurate and up to date map data available.
The PDA version of iGuidance has a great interface and a slew of nice options (points of interest, voice navigation, 3D mode, night display). The PDA version of Microsoft's S&T doesn't even compare.
Feel free to PM me if you have any additional questions.
Spence