So, not coming to Amsterdam, then? There's more to see here than drugs
Congrats on your marriage! I don't live in Europe, so I have nothing else to add.
In many European towns, mainly the centers, you'll probably have trouble with one-way streets, walking-only area's and narrow streets, mainly in the older cities.I know that Hertz operates in the Netherlands, at least. And they seem to have GPS systems for rent, too (Hertz NeverLost®). You can also check out Europcar, which apparently is supposed to be the biggest car-rental company in Europe.
It is very likely that handheld GPS systems will have a problem working/connecting in many of the older city centres, but there are usually free maps available at the hotels covering the city centres.My phone GPS does not like small narrow streets and high buildings, so I often have to use a map or try to find some open areas to connect to the satelites.
@ comis, I like your statement ~Maybe not this time...I pretty much let my wife to decide where she likes to go, and personally, I would rather to go a fewer places each time to explore more in depth to each city. you are either a very wise man or this isn't your first 'marriage' ?
Also worth noting if you're driving from country to country is that some of them charge you for use of the highways in different ways. German Autobahn is free (for non-German folks at least ) but you have to buy a Vignette (sticker you have to have on your windshield) in Austria and Hungary. I usually buy them on gas stations as soon as I enter the country but it looks like you can buy a e-version of it. Never tried it though. http://www.tolltickets.co.../vignette.aspx?lang=en-GBhttp://www.tolltickets.co.../vignette.aspx?lang=en-GBYour rental car should probably have one on already but I'd check anyways.
As far as London goes,I'd really not bother with the car,as its madness getting around by car. Public transport is more efficient than we let on,and,as long as your not traveling in rush hour,not that expensive. Get a London AtoZ map book,and do it on foot,bus,boat or tube!