Only 3 days in Tokyo

We have only 3 days in Tokyo 19-21 dec. What are the things we must do or see in this short time? Adults traveling with teenager and toddler. All love eating, shopping and trying out new things. Any recommendations?

http://www.tokyodisneyresort.co.jp/en/index.html

http://www.hatobus.com/en/index.html

http://pr.enjoytokyo.jp/111202roppongihills/

For shopping, I'd go with Shibuya for sure. If you like high end fashion brands then you'd like Ginza and Omotesando Hills. Odaiba has lots of shopping too, but lots of attractions such as Joypolis, Toyota Megaweb, etc. If you're there on a Sunday and want to see the youth culture, Harajuku and Yoyogi Park are fun to wander through and shop at. Tokyo Dome has amusement rides, but your teen will probably miss out on the best one (thunder dolphin) as it may still be shut. Sea Paradise at Yokohama offers an aquarium and rollercoasters though.

Thanks for suggestions. We will definitely be shopping around shibuya. Probably want to catch some sights too. Not sure if we should make a trip to mt. Fuji or take a train to kyoto. Still undecided. If not, will just stay in tokyo and move around.

If you've only got 3 days in Japan you're better off staying near Tokyo, as you'll waste too much time travelling around. As it is, you'll find that 3 days will limit the amount of stuff you can do in Tokyo alone. You can see Fujisan from some places in Kanto on a clear day if that helps at all.