We're heading to France in a month for a wedding, maybe two hours' drive outside of Paris. It would be helpful to have some kind of nav system, that I buy before we go, which speaks English and has European maps. Obviously, I'm looking for something of the "portable / car" variety, and some sort of real-time traffic would certainly be helpful.

Thoughts on this? Tom Tom vs. Garmin vs. whatever else? I suppose another alternative is to pony up for a data roaming plan for my iPhone and use that -- probably cheaper than buying a dedicated nav system, but will I get good data service between cities in agricultural regions of France?