my advice: get a train to amsterdam. it only takes about an hour and you'll see the real bad boys of architecture! There's a fantastic art gallery in rotterdam with some amazing installations, cant remember the name. I know the red light district is seedy but if you wanna have a really good night, its the place to go, in amsterdam anyway. Dam square woth a visit too. There's an absolute wealth of beautiful buildings all over. Check out borneo island if you do end up in amsterdam...amazing housing scheme and its just a short bus journey from centraal station.
But apart from that, kick back, relax and spark up a fat one for me!
and yes you gotta do the cofeeshops man its part of the experience!