Potsdamer Strasse Berlin is definitely an area of Berlin to hang out. Lots of new and old places to visit.
p98, Odeeh, Murkudis, Wintergarten, Bauhaus Archive, Nationalgalerie, etc.
And now another reason to go. Paul Smith opened a store. A beautiful Store in the former devotional objects store „Ave Maria“ (which is now located in Lützowstr.)