Gorman makes good stuff. You can remove some of their products and walk around with them. It's a monitor and GPS that sits up on your dash with beanbags.
If you want something more integrated, get an Alpine LCD head unit and the Alpine DVD GPS system. You can get an Alpine LCD head unit from $700 on up and the navigation system for $1200
. I'm sure other companies make good products too.
Please note that you can get a GPS system that interfaces with a computer (such as a laptop that you can bring along) over the USB port for only $80. Hope this helps. CompUSA's GPS stuff