A place where I spend some time almost everyday is the Marheineke Markthalle on Bergmannstraße in Kreuzberg. It's just around the corner from where I live and a great place to buy fresh food and products from local farmers or all kinds of delicatessen from different countries. Many market stalls also sell freshly prepared food and it's always busy at lunchtime. For saturday mornings try the original french croissants.
The central ‘Mitte’ area of Berlin is packed tight with galleries and museums, which means you can cram a lot into a short amount of time, if that’s what you want.
The best of the lot is the Me Collectors Room, which shows off large chunks of the Thomas Olbricht collection alongside other contemporary private artworks. The permanent ‘Wunderkammer’ display offers over 200 pieces from the Renaissance and the Baroque periods, with a solid focus on the strange and macabre. There’s even a Mark Ryden original that fits in nicely.
This museum of photography is really great, and the highlight for me after the inspiring exhibitions is the good coffee and great cakes at their coffee place.
I find myself there almost every second week for a drink and a slice of cake. The food is perfect, the ambiance is nice and it's really alive as a lot of people are coming directly from the running exhibition. At the entrance you can find an interesting bookstore and the best photoautomat of the city right outside.
Last but not least, it's only some meters from the Helmut Newton Fondation ( which doesn't have a nice coffee place itself yet ).
Berlin has plenty of magic cafés in every corner. This is one of them. It's quiet and it has a mixture of lights and furniture that really catches me. Cakes and coffees are also very tasty.
A very good reason to travel West: the C/O, next to the formerly infamous Berliner Zoo tube station, is an awesome museum dedicated to photography and visual media. Previous exhibitions include Larry Clark, Martin Parr, Anton Corbijn, Annie Leibovitz and Stephen Shore.