When I was in Japan, I went to Tokyo for two days. Since I was only going to be there for two days, I wanted to make the most of it, so I made a list of the places I just had to visit, and one of those was Tokyo Tower.
I went at night, and the view was amazing! It would've been nice to see it during the day, though -- pretty much every angle was the same thing, lights and cars on dark streets.
The ground floor of the tower was really, neat, too! There were lots of displays with the history of and information about the tower.
Also, when I was there, they were getting ready for a Michael Jackson event that was happening soon, so they were playing nothing but Michael Jackson songs there. His face was also everywhere there.
Definitely worth a visit if you want to do a little sight-seeing of Tokyo! You can pay a little extra to go to a higher observation deck, too! You have to wait your turn, but even though it was crowded when I went, the time passed really quickly. :)