If you just want an occasional bit of assistance with your journeys, Google Maps Navigation will do the job for free. But if you need a few more features, and particularly if you plan on travelling in Europe, where mobile data roaming charges could be prohibitive, a standalone app with local maps makes a lot more sense. Navigon's MobileNavigator for Android is a little pricey, particularly when you consider the Western Europe version of TomTom for iPhone costs the same as the UK and Ireland version of MobileNavigator. But you can't get TomTom for Android yet, so MobileNavigator is worth considering, although we would recommend running it on a more recent handset than the G1 we used, for a more fluid interface.
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