I just purchased a Garmin Nuvi 660 for my new car. I did a lot of research and looked at many different GPS units. I feel this was the best choice. It is very user friendly and extremely accurate. My wife has a factory GPS in her BMW X3 and a friend has a factory unit in his new Accura. I like my Nuvi better than either of those. The only downside is they are a little pricey. The best price I found was though Amazon.com for $704. If you get one, and have a fairly flat top of your instrument panel, I would recommend getting the beanbag mount with the gooseneck made for the 660. It is very secure and works very well. I perfer this to the suction cup windshield mount because you are able to position the unit closer to you since all inputs are through a touch screen. Good luck.
I have had my Garmin 360 for almost a year now and have yet to get lost. This model only costs around 600.oo It's really easy to install and use. I like the suction cup mount onto the dash of my pick-up truck.