Originally Posted by henkybaby

It will take you 30 minutes to get to the train station (if you're lucky) and at least another 30 minutes to get to Amsterdam Central Station (if you're lucky) so that is already one hour gone (if you're lucky). To get back you need to make sure not to take the latest possible train but one before meaning that you will arrive at least 1:30hr before your flight departs. So that is at least another 2 hours gone (if you're lucky). So, deduct 3 hours to get to the city and back.

That leaves you with either 2 or 5 hours in Amsterdam. The first would be way too stressy so at least take the 8 hour (net 5hr) option. You can walk to a lot of interesting stuff from the station. Just head out cross the busy 'square' and walk the length of the Damrak to the Dam. You can simply hang there for a bit, have a coffee or a beer and maybe even visit a museum. You can also keep strolling across the canals and enjoy the atmosphere.

Red light district: absolute nonsense to go there.
Canal Cruises: if you must. Might be an idea if it is raining. It is much nicer to walk though. Amsterdam's city centre is relatively compact. Not like London or Paris.

Walking around Amsterdam is best done when it is sunny. When it rains we all stay indoors.