I would recommend Amnesia coffeeshop, Herengracht 133.
Good call Doc, I haven't been there in forever but it's a nice place inside.
For an upscale coffeeshop try the Dampkring.
If simply posting some goon at the door ordering customers to remove their hats upon entering qualifies a place as "upscale," then yeah, there's Dampkring! I haven't been there in years and don't plan on returning. Perhaps it's changed now.