Your tips Take a Trabi tour, and a boat ride on the Spree. That will show you Berlin in a very nice way.
For me, with interests in WW 1 & 2, Berlin is the place where a lot of history is made, and still is visible. The historic places are really worth a visit, and the difference between the former East and West part is still visible, but it changes.
Also for the wife there is a lot to do and see, like the Kudamm, Europaplatz and the new shopping district on Alexanderplatz.
So we like Berlin very much, and visit it, also for the famous Country Music Meeting, twice a year at least. What also is really well organised is the public transport. inside the circle line you dan't have to wait longer than 5 minutes, outside it is 10 minutes. And the colour will guide you to your destination.