The 9 Streets
This is a very special shopping area between the the Raadhuisstraat and the Leidsestraat. You will find many nice small boutiques. A few of the 9 streets:
Runstraat / Wolvenstraat / Huidenstraat / Reestraat / Hartenstraat

Diamonds
Amsterdam once was a major diamond centre. There are about a dozen diamond factories in Amsterdam and about five of them offer a guided tour (for free). The most famous ones are:
Coster Diamonds (picture) and Gassan Diamonds.

Cheese
Another famous (export) product of Holland; cheese.
There are many cheese shops where you can buy and taste the enormous varity in cheese.

Markets
Waterlooplein (picture) | mon-sat | second hand goods
Albert Cuyp market | mon-sat | general goods and food
Flower market | mon - sun | flowers