What about the language barrier? Is English prominent enough in Amsterdam to easily get through everyday interactions or would you need to learn an entirely new language in order to truly enjoy the city?
People often explain it as kindness, but it's really just plain rude laziness: for many Dutch people, speaking slow and clear Dutch requires a lot more energy than upspeed English. Let alone listening to and trying to understand broken Dutch.
Though funnily enough I will (during the summer) quite often get addressed in German when I enter a shop, at which point I haven't even said anything yet nor do I speak German.
If you want people to take the time and trouble to speak Dutch, consider asking them, preferably in a context without time constraints.
edit: oh Skrebbel, I see now it's you and I know you're Dutch. Point still stands though :)
Everybody everywhere speaks english: shops, public transport, you name it. Even children, since the TV shows are in english with subtitles. Movies at the cinema are not dubbed and have subtitles as well.
That said, outside of Amsterdam, some rudimentary Dutch helps a lot, especially if you're using public transport. Also, even just trying will automatically garner you a little respect with the locals, they're a bit sick of people who don't even try. ;)
The only time I needed to use any of the Dutch I had learned before coming was with some immigrants for whom English would be their third language.
Paperwork is in dutch, but you get plenty of help everywhere.