I'm with NJ John on this one, terrain all the way; my favorite all time piece is the Arnhem bridge that I saw for the first time at OTSN in 1997? I think, maybe 1996. Just stunning, imagine that with the new 250/1, Normandy kubelwagon, Berlin armored car, etc, etc and the new Germans storming across with the new Airborne figures holding on for dear life.
Surround the bridge with JG Arnhem buildings and that is one magnificant display.
A close second is the Stalingrad strongpoint, a real beauty............