Amsterdam is a city that is best explored by walking. The main sites are all pretty close to one another and any nook can offer a store worth exploring. The streets and lack of parking make cars an inconvenience. Too much walking though can get to one's feet, and when you start to feel an ache, it's a good time to hit the canal tours.
A number of companies near Centraal station and along the Damrak offer canal tours of the city. They all are similarly priced and the routes are all pretty much the same. All the boats are also more or less uniform, being long, low boats with glass canopies. The tours have recorded narrations of the sites you'll see, and the short descriptions are offered in Dutch, German, French and English.
Being as the canals are low to begin with and that these boats are pretty deep, you'll find yourself looking up a lot. Also unless you're on a water taxi (which isn't a tour), you have no chance to get out and look around. The canals only can get you so close to some sites, and therefore you don't get to see the likes of the Royal Palace or Dam Square.
What you do get to see however is the impressive artwork along the bridges, as pedestrians are not able to really appreciate. Also, these canals were the lifeblood of the city centuries ago. Back when shipping was the Dutch financial backbone, the canals were used to transport things products to and from the docks.
Because of the design of the city, there are no bus tours of the city. The canal boats are the best alternative. And it offers some insight into the past. As the saying goes, "When in Rome, do as the Romans do." So when in the Netherlands, take an hour to do as the ancient Dutch did.