I highly recommend visiting the Edo-Tokyo Museum. It is full of replica buildings (including a full bridge spanning one of the floors) and super intricate models depicting life in Edo.
Seconded. It's a fantastic museum. And oddly space aged building considering the antique contents...
Located nearby, on a much smaller scale, there's a similar juxtaposition of interesting contemporary architecture and older Japanese art - the Hokusai Sumida museum.
For anybody who likes Hokusai's wood-block prints, the one-room permanent exhibition has excellent multimedia content.