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 Zoo and the Aquarium is on the things that never changed during the years. Everytime I visit it looks exactly the way when I first went when I was a little child. This place gives me a lot of inspiration, I like the way they want to make the cage enviroment look natural with artificiel light.
A good place to drown your Berliner winter-melancholy. The bartenders are top notch and the interior is warm but stylish, with the inevitable retro vibe. Open from 6 till late. There´s also a legendary (and kinda expensive) restaurant next door, which provides the bar with some excellent snacks. Works for dates and for friends, but if you´re planning for a bigger group it might be wise to reserve.