We bought another city guide from the same type that had served us so well in New York, featuring lots of walks through the city, with key highlights pointed out. Again, the guide took us to interesting places -- next time we go somewhere, I'll see if they have a guide for that place too.
To me, Berlin seems a lot like Copenhagen. However, Berlin seems less... polished. It's definately a city with a recent history (the Berlin Wall) in a country with a recent history (the division and WW2), and the scars of those events are still there. Near to the loft, on the Kastanienallee, there was a big building with "Capitalism kills" written on it in large letters -- that's not something that I would expect to find in Copenhagen, but it's there in Berlin.
We had a good time, but we didn't feel quite at home like we do in Tokyo or like we did in New York. I'll recommend it to anyone, but I'm not sure if we'll return any time soon.