Finally got to see the film this weekend (though i'd seen perhaps all of it as a kid, it'd faded from view.)
First thought on watching the march of the workers was a piece of art of my own, which in turn had been influenced by Piranesi and things that had been influenced by Lang's film like Star Trek's the Borg and the Matrix. Please see images of it and accompanying artist statement here: http://www.thedetroiter.com/APR04/ns_billboard.html
Another quick note, randomly stumbled on artist Michael Kaluta's website and noticed a link for "Metropolis" drawings he'd done for an illustrated book on it. It's stunning and very human work - well worth checking out: http://www.kaluta.com/pages/metropolis/metbook.html
One last quick thought - intrigued by how much silent film resembled a comic book - overly dramatic acting to carry the content through action over words, the insertion of captions.
More thoughts coming later... - N