For sitting and having a drink and a bite:
Prix d'Ami
Coffeeshop Amsterdam
Barneys
Boerenjongens
Eerste Hulp
And don't stay in the center, head out to De PIjp!
One address I like a lot is Club Media. Also, Papillon, at Van der Helstplein. Lastly Katsu at 1e van der Helststraat, just off...