The night images are amazing and they spent so much time spraying the streets every night with water to get that look.
I'm also so glad the director fought hard to avoid the typical movie score that was pushed by Hollywood producers and went for the iconic sound of the zither [0]. Which all happened by accident when Reed was having a dinner and hears Karas playing the instrument. The choice of this instrument not only made the movie but also change the fortune of Karas who was playing the instrument [1].
Along with the best improvised movie lines which I would include the Bladerunner I would also include Orson Wells' line about the Swiss and the cuckoo clock.
As a bit of a movie buff, I have to agree with Soderbergh's comment about the movie keeping the consistent tone. So many movies with great potential lose their tone and miss that quintessential part of the movie that makes them a classic. The Third Man is a classic and should be a must watch on anyone's list who likes the cinema.