Originally Posted by
John
Checkpoint Charlie, Brandenburg Gate, and the Reichstag are the three that come immediately to mind, along with the wall but there's so much of that left that you don't need to be looking for it to see it, and if you want to walk along it Checkpoint Charlie is a good place to start anyway.
In terms of places that are just good to see, there's Alexanderplatz and Potsdamplatz. There's a little museum/gallery in a church just off Alexanderplatz but I forget the name of it. I imagine it'd be very easy to find from the train station.
How long are you going for?