I lived there 08-09 when I was getting my masters degree, so I apologize if any of this is out of date.
First of all, this is a good reference:
http://www.coffeeshop.freeuk.com/Map.html
A rule of thumb is, the closer you are to Dam Square, or central station, the pricier and more touristy the shops.
That said, I always liked Abraxas right off of Dam Square. It has a cool vibe and is a good place to hang out if it’s not too busy. I used to study there. Well, attempt to anyway. The apple jack is nice, though nothing to write home about.
For something more off the beaten path, head over to Paradox to the west of the dam, it’s more of a local’s shop, with a friendly homey atmosphere. Their chocolope was the fruitiest, tastiest strain I found anywhere.
As was mentioned, the rokerij are cool, my favorite was IV, a ways south of Paradox; it has amazing Buddha murals on the walls. Great place to space out.
Another one of my favorites was Old Church, in the heart of the Red Light District (next to a church). It has a seedy charm to it. The second floor is a great place to observe the goings on of that part of the district. Also, it’s seasonal, but if they have it, get the Lebanon red hash, one of my all time favorites.
Also, for hashes to knock you on your ass, check out Tweede Kamer or Dampkring (owned by the same people). I never hung out there because they were always too busy, but they have the best hash selection I found anywhere. I’m pretty sure the Super Tiblisi is opiated. The bud is top notch, too.
The Greenhouses have very good, if somewhat spendy, strains, though I never cared just to chill there.
If you like volcano vaporizers, and still have the cognitive capacity to use them, check out the Bluebird. They have them sitting out for customer use. The Northern Lights x Blueberry and their version of Super Skunk were both good. Never tried their hashes.
Well, I could keep going, but don't want to give you information overload. Have fun!