I have to chime in on Tsukiji.
I had my doubts about visiting a fish market, but everyone seems to swear by it so I thought I'd give it a go.
I wandered through the stalls and while it was interesting to see the massive amounts of seafood on display, I found the chaotic scene off-putting. Forklifts whizzing around, people lugging carts, narrow aisleways, dirty looks from fishmongers trying to do their jobs without interruption... I don't know. It felt like wandering into a warehouse and looking around while the workers did their thing.
It is a marginally interesting place to visit, but I can't see how Tsukiji has managed to attain such lofty destination status in Tokyo. The only reason I can think of is because there are few other options for jet-lagged foreigners who wake up at 4 am.
(I did, however, enjoy the sushi and biru breakfast I had there!)