When I first saw this I was totally blown away by its beautiful animation and groundbreaking use of music! It really made me lyrical in a way few anime does - Rintaro and Otomo really has what it takes to make a masterpiece. The blend of charming old-fashioned technology and allusions to modern phenomenons makes it the perfect anime for the beginning of 21st century!
Metropolis is based on Tesuka Osamus first manga and later gave inspiration to his more famous "Astro Boy". Some story elements and characters from Tesukas later works are clearly inserted in Metropolis to make it work as a movie, which in this case is good... The choice of music is, in my opinion, daring and rather funny; jazzy tunes spiced with hits from the 60s (Ray Charles) sets the tone of the "optimistic atomic age". All in all, well made nostalgia...
I could go on forever with this rant, so I spare you that if you see this little animated gem! Rent it, buy it, steal it (if necessary ;) , you won't regret it!