You say that detailed maps of other countries have to be bought individually for the TomTom Go - roughly how much and how are they transferred to the unit?
Current TomTom website shows too much messing about with linking mobile phones to the TomTom Go 500 and 700; the mapping features of the 700 seem ideal - but I wouldn't pay for that bluetooth or mobile phone crap... And the -300 doesn't seem to include a European major routes database.
Whilst not that seduced by whizzo electric toys, a simple standalone like the TomTom Go seems easier than fighting with MS Autoroute print outs at speed with the roof down!