I went in June of last year. Wonderful place with mostly friendly people... they love foreigners! The people my age are a bit on the wild side when it comes to fashion and hair styles. You must go to Ginza and the Tokyo Fish Market (forget the Japanese name for it, but it's huge and is lined with restaurants that sell fully prepared seafood meals to businessmen). I took a picture of myself with a giant tuna head! At one of those restaurants, my friends tricked me into eating soup with a shrimp head in it.
There are 4 taxicab companies (I think), orange, green, white and black with slightly different fares. The neat part about them is that they have automatic doors... so watch your fingers!
If you plan on using the subway lines alot... I suggest that you use the Japan Rail Pass. However, I think there are several rail companies which serve Tokyo so your choices in destination may be limited. However, it is quite convenient, not to mention cheap to use if you plan on traveling to other cities like Osaka or Kyoto via Shinkansen (A really, really awesome ride... it's like a jet on the ground and it is very comfortable even when you're not in a Green Car). I highly recommend Kyoto due to it's many, many beautiful temples and it's a great place to pick up some traditional mementos (pottery, swords etc.) Tokyo may be a bit more pricy and tacky when it comes to souvenirs. If you do decide to take a sword home remind your store clerk to write you a replica authentication form for the Japanese airport customs. They will not let you leave the country with a real, sharpened sword unless you apply for a government permit (but real swords are really expensive 90,000 yen or so) Replicas are cheaper and easier to take out of the country.
That's all I can think of for now...
"Are you a pretender... or a thoroughbred?!" - Professor Matt Miller