There's nothing more revigorating during the dark winter days than spending a couple of hours in a sauna. Germans have mastered the art of sauna and you can find amazing pieces of architecture in the public swimming pools (Stadtbad). I find Stadtbad Neukölln very peculiar in its neoclassic architecture and it's definitely a wallet-friendly option to enjoy some sauna time there. Be prepared to be naked in front of man and woman!
ABC is Berlin´s Eggs Benedict Mecca. This laid-back, fun little shop will provide you with one of the city´s best Aussie brunches - provided you reserve or are willing to wait for some time. But the eggs, the coffee and the Bloody Mary really make it worth.
Beautiful atellier-stores around weserstrasse, this is from a very nice girl that make "sculpure hats" as she said. Excellent record store across the street also.
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.
The Tempelhof Airport is now closed and they have transformed the landing field into a public park area. As soon as you go there you notice that usually you don't get to see that much sky in the city so entering this area for the first time is quite overwhelming. I especially love the old softball fields that have been built during the American occupation.