I'd give a thumbs up for the TomTom package, I use TTN3 with an ipaq 5550, all the maps of GB fit onto a 128mb sd card. I use a Syson 'bluetooth' GPS receiver and as a whole it all works very well.
For mounting in the car I use a Seido powered (built in loudspeaker with it's own volume control) mount that clips onto the vents, it's ok, but for a more secure mount I think I'll get a 'Brodit' and mount the Seido onto that.
............and cost I bought all the bits off ebay
