Odaiba is a man-made island type thing around the Tokyo Bay area. Generally not that much there to do bar from walking around and looking at 'proper Tokyo' from the other side of the water. Seemed to be the place to go if you want to walk your dog too. On a side note I've started noticing people doing photo-shoots of their dogs, with some dressed up in strange dog clothes. It's weird.
The Imperial Palace is near the main Tokyo station. (Yeah, smooth segway) A note about train stations: whereas in England a big train station will consist of a few platforms and maybe a Starbucks and WHSmith, in Japan it's possible to go to a train station and never actually set foot outside it. Supermarkets, restaurants, hairdressers etc. can also be found in them.
The area surrounding Tokyo Station is fairly posh with designer shops and branch headquarters (I think) of the big Japanese companies. And there's a palace. Which is also quite posh. Innit.
Tomorrow I'm revisiting Yokohama. If it doesn't rain.