The Tokyo metro is totally awesome, there are trains every few minutes and they always seem to be on time. I only wish we had such effective mass transit in the bay area (though I can somewhat understand why we don't given the relative difference in population densities). In the two days in Tokyo I was able to cover a lot of different sights getting all around downtown Tokyo with relative ease using the metro. Definitely get the day pass, which at 1,000 Yen is a great deal. Pictured above is a commuter waiting for the arriving train. I exposed for 2/3s as the train was going by coming to a stop.
One of the things I managed to see before heading to the airport was the Sensoji Temple in Asakusa. It is a Buddhist temple and the oldest such temple in Tokyo. Walking up to the temple is an array of shops filled with interesting craft items which make for great gifts. Sadly I couldn't find any origami paper there, nor anywhere else I looked, guess I'll just have to go back :).
The picture on the left is the 5 story pagoda or Asakusa shrine which was built in 1649 (the main building was built in 628).
Well after 2 1/2 weeks of travel, in about 30 minutes I will get on the plane to return home, definitely looking forward to that.