One of the best places for coffee in all of Amsterdam is De Espressofabriek in the old Westergasfabriek (to be found in Westerpark), although its official address is:
Gosschalklaan 7. http://www.espressofabriek.nl/westergasfabriek.html There is another outlet at Ijberg (a supposedly trendy part of Amsterdam on one of the harbor islands, but in my humble opinion that place is basically a Vinexwijk for well connected middle-class families), but I won't go there.
The coffee is absolutely superb; even Italian tourists are impressed. (A bunch of them found their way to the usually very quiet upstairs--the stairs are hidden behind the barrista's.) The brownies and muffins are addictive, too. Better yet, the place has free wifi (and clean toilets); the password is... But foodies will be left hungry. Worse, on sunny weekends (admittedly rare in Amsterdam), the place is a zoo. The lead manager of the place is a terribly self-satisfied barrista, who thinks of his craft as an art that needs to be admired slowly. Moreover, he doesn't mind letting tall blondes skip the very long cues that develop due to his out-sized narcissism. But when he is gone and on ordinary week-days, the place is among my favorite hide-abouts. The barristas live all over Holland, and they make long trecks (treks?) to serve the very best coffee to a growing group of appreciative customers.
Note to the computerfreaks: I have been unable to find a picture of espressofabriek on google.pictures.