[gargamel]

I was in Hokkaido (Sapporo) and Tokyo a few weeks ago and really enjoyed both places, though they're very different experiences. The seafood in Hokkaido is amazing, as is the miso ramen, but a few days there would be enough. Flights are fairly reasonable, but your time may be better spent closer to Tokyo (Kyoto and possibly Nagano to see the snow monkies).

The Robot Restaurant is still worth going to, but it's a bit tamer/more family-friendly than it was a few years ago. Not that it was ever too risque, but there used to be a lot more dancing girls in bikinis, for better or worse. In the same neighborhood, I'd recommend Jinomaru Yakiniku for some delicious grill-it-yourself Japanese beef.

Other food highlights in Tokyo are Ton Ton Yakitori (a recommendation from Anthony Bourdain), Akaoni sake bar in Sangenjaya (a recommendation from a Japanese stripper I used to know), Sarashina Horii soba (Bourdain), Butagumi tonkatsu (stripper), and Fukuzushi sushi.