It's really a funky place; I like it a lot. It helps that a very large percentage of people speak perfect English. I wouldn't think so much about going out to the countryside (which I don't think is particularly remarkable, just judging from train rides through it) as in staying in downtown Amsterdam. There's a central railway station right in the heart of town, and you could spend most of a life-time walking around shooting within a mile or so of the place. Great shots of people and architecture, cafes and canals...but they've also got a couple of the great art museums in Europe there, and both are worth a look for anyone interested in any visual art. If you get to know the train station you find you can make fairly long day trips to some pretty far-away places, and still make it back to your hotel at night. I'd be a little careful at night, though; sometimes it can get a little too funky.
Actually, when I think about it, asking what to shoot in Amsterdam is like asking what to shoot in New York. I mean...everything.