I'm jealous. I haven't been to Berlin since I was stationed there in 1972-73. I'd like to see the Museum Insel (the center of town, with the best-known architecture), walk down Unter den Linden and through the Brandenburg Gate, visit the huge urban renewal project at Potsdamer Platz (which is supposed to have some remarkable new architecture), and tour Sanssouci Palace in Potsdam. I'd like to ride the S-Bahn, since I wasn't permitted to do that when I was there, and I love trains.
Then I'd probably go to Steglitz, since it was my favorite shopping district when I lived there.
Oh, and if you haven't been to a German department store, visit KaDeWe.
Have a good time.
-Joe Offer-