David, I went with the Garmin Nuvi 680. Love it. I know you want an in-dash, but you might still want to consider this option. There are a bunch of different mounts now too for portible GPS. Everything from air vent mounts to cup holder mounts.
I can take it from car to car. Business trips in the rental car...and etc.
A good site for price shopping these are:
www.pricescan.com
For mounts:
www.mountguys.com