Most aviation oriented car drivers and aircrew will want the penultimate GPS Navigator which has the capability for the insertion of multiple way points in Lattitude and Longitude and ideally map references as well.
The ultimate unit will be combined with a UHF transceiver, mobile phone, distress beacon, camera and will you then want music as well? This ultimate unit will also need to be compatible with that second satellite system which may already be up and operating.
Until the development costs for the present spate of units are recovered and prices become reasonable I will be content with my hand held Magellan GPS315 velcroed to the instrument panel or the car dash. It currenly contains 150 of my carefully collected way points for future reference and route planning.