Sadly not enough time in Tokyo but Japan is certainly on the map for further exploring. I'll be flying back to Germany via Osaka sometime in March.
Fish fans must see the Tsukiji fish markets. It's worth getting up early or staying out late to see the 5.30 am auctions.
Update:
Barbara at Petites et Grandes Aventures made this snappy little audio slide show of the fish market with a Canon Ixus 950 and a demo version of Foto Magico. Audio captured in the camera movie mode and tweaked in Audacity. Not bad for a couple of hours of fun on a rainy afternoon.