As you walk up the Damrak from Centraal Station you will see the Grasshopper on you left (avoid this place), but if you turn right on that same street (actually a small alleyway) you will see a sign that simply says 420......across from the 420 is a wonderful bakery.
The 420 or cannabis cafe still sells alcohol has a great laid back crowd and atmosphere and plays the best music of any coffee shop I have been in. Zappa, Stones, classic 70's rock.
Their cannabis/hashish selection is good also.

Always very attractive women working the bar.
Always gets great reviews from those who visit.