And some good old fashioned graffiti, dirt and grime. Not to mention city rain with iconic shots of Batman in it.
Each film's city had a particular look that separated them from the others. They were almost like different cities completely. I loved how it looked in Begins, specifically that scene where Wayne is in that hat/hoody disguise outside the courthouse, watching Rachel and Finch by the phone. That grimy, claustrophobic feel really reminded me of Anton Furst's '89 Batman Gotham. I also liked all the shops and weird denizens that were walking around that are non-existent in Dark Knight and TDKR. Who can forget falafel guy! It was like a different world. I know people gripe about it being a "studio built set", but I find that very admirable. Any time you're building something out of nothing, especially places like the Burton Gothams or Arkham and the Narrows, that should always be commended. People seem to forget about the artisans that put time and work into it and are too quick to write off that specific, visual look as "fake". The only thing I don't like about Begins' Gotham is that horrible CGI look it has during skyline shots. It looked like at some points they just plopped in this brown, crappy looking city into the actual location and it's obvious as hell. It's REALLY bad when the Narrows gets gassed.
Being from Chicago though, I was really saddened to see them drop the location completely after Dark Knight. Everything from the accents, to the locales, to the actor that played Wuertz (a native) just screamed Chicago. It was very much "Gotham" until TDKR came along.