I went on a Rhine river cruise a few years ago with my family... We passed through the Netherlands, stopped in Amsterdam for a day or so (I didn't smoke pot then, so I didn't know about it), and I really liked it. It was a BEAUTIFUL day- we went during tulip season, and the colors were phenominal. The concentric canals were also pretty damn cool. The people were VERY friendly as well.

I'd like to go back again some day, but the pot would simply be an accessory to the trip.