Don't forget the Brandenburg Gate, and what's left of the wall. IIRC there's an aircraft museum not far from Berlin too, let me look.
Yes, there's the Luftwaffe museum at Gatow:
http://en.wikipedia.org/wiki/Luftwaf...der_Bundeswehr
http://www.aviationmuseum.eu/World/E...Bundeswehr.htm
Looks like quite a nice collection there of aircraft from both sides of the curtain.
A bit more sinister is the Stasi Museum:
http://en.wikipedia.org/wiki/Stasi_Museum
Or The Memorial
http://en.wikipedia.org/wiki/Berlin-...ausen_Memorial
The Glienicke Bridge
http://en.wikipedia.org/wiki/Glienicke_Bridge
DDR Museum:
http://en.wikipedia.org/wiki/DDR_Museum
Obviously, I defer to those with more local knowledge as to whether these museums are worth the visit, but certainly there is a lot of history in Berlin itself and the surrounding environs...that which survived it that is.