There are so many to choose from so hopefully this will help a bit... my advice stay clear of large neon signs!
One of our favorites is The Dolphins, wonderful coffeeshop, go sit downstairs, the atmosphere is much nicer with circular couches and tables. It is dimly lit with a couple of windows to the outside. The room is painted with a under water theme with blues and greens from floor to ceiling. Upstairs is more bar like, with more of a party atmosphere. They offer coffees, drinks and a wide assortment of pot and hash.
Their hours are Sunday-Thursday 10am-1pm, Friday and Saturday 10am-3pm
The Dolphin Coffee Shop is located at Kerkstraat 39 on the Southern Main Canals near Leidsesplein.
The Grey Area is great, SUPER small, owned by two american guys, the music is good here - one of the only shops to not play dance music. They have bongs for customers to use and they are very friendly. Unfortunately the place is so small and can feel a bit cramped, but it is still a great spot to check out. Their pot is amazing and you will leave a happy camper.
Their hours are Tue-Sun 12pm-8pm
The Grey Area is located on Oude Leliestraat 2 in the Western Main Canals and Joordan area.
Homegrown Fantasy is a nice coffeeshop as well, searving alot of coffee and drinks. The shop is also an art gallery, so there is always stuff to look at. The place is more modern and large, but still comfortable. You can check out their website online at: http://www.homegrownfantasy.org/.
Their hours of operation are Monday-Thursday 12-11pm; Friday-Sunday 12pm-12am. They are located at Nieuwezijds Voorburgwal 87a in the Centrum district.
Smokey Coffeeshop is a not-so-great coffee shop. This was my first ever coffee shop and we learned quickly that it would be our last visit to Smokeys. Nothing was really horrible about it. It was more bar like and very touristy. Nothing special. The pot was OK. The fact that they had a bouncer at 10 a.m. was a little odd, but who knows how this place works as a first-timer. It was right across from our hotel and the large, bright neon sign was calling our names. It lacked that comfortable quality that you learn to love and expect when entering a new coffee shop. They have a website you can visit online: http://www.smokey.nl/Home.htm
They are located at Rembrandtplein 24 in the heart of the square.
Finally, The Grasshopper Two, the most well-known and largest coffeshop. It is very touristy, especially since it is the first coffee shop outside of the train station. It is more of a bar and club than a coffeeshop. It is nice, but there are alot of other shops in the Dam worth visiting. The pot was good, but not amazing.
The hours of operation are Sunday-Thursday 8am-1pm, Friday and Saturday 7am-3pm
They are located at Oudebrugsteeg 16 and the Grasshopper One is located at Nieuwezijds Voorburgwal 59.