My wife and I have been through the Netherlands twice.  If you're in the vicinity of Amsterdam, check out the windmills at Zaanse Schanse, just northwest of the city.  Its easily accessibly by train and you can see a few working windmills.  Check out the mustard grinding windmill, we bought a bottle and wish we had purchased more!  Southeast of Amsterdam is Utrecht, a much smaller and slower town than Amsterdam, still built on canals.  Spend a day there wandering around.  If its market day, you can pick up cheaps eats such as local cheeses, bread, pastries, etc.

In the southern end of Holland, squished between Belgium and Germany is Maastricht, a small college town spanning the Maas river.  We spent a day there enjoying the friendly atmosphere while trying some local food and drink.  Maastricht is very laid back and a great place to stop if you're in Koln (Cologne), Germany which is just across the border.

Enjoy!