The Rijksmuseum, Vondelpark, the Jordaan (where the locals hang out), the Bejinhof, the traditional bars along the top end of Zeedijk (not the Chinatown end).
Depends what you like - I'd certainly agree with the Van Goch Museum and the Rijksmuseum. The Anne Frank House is worth a visit but you may have to join a long queue, depending on the time of day you turn up. The flea market in the Waterlooplein is entertaining, too. There's a fascinating little Theatre Museum, but I can't recall its address offhand - it's in a canalside house, and it'll be in a guide book somewhere.....