I moved to Tokyo in 2007, and my appreciation for camera stores, which was already considerable, markedly jumped when I switched to film earlier this year.
I am about a 30-minute walk from the Shinjuku Yodabashi, and the dedicated film outlet is wonderful. However, my favorite store is actually the nearby Map Camera (
http://www.mapcamera.com/), which has a sizeable supply of used Leica, Voigtlander, Mamiya, Canon, Nikon, Olympus, Pentax, and so on.
Even closer is a dedicated Leica dealer in Kabuki-chou, Tokyo's main red light district, thus offering one the concurrent experience of a "Nevada whorehouse" and Leica toy store. Also in Shinjuku is Lucky Camera, which sells a number of used Leicas, Hasselblad, Rolleis, Nikons, and such.
And there is always Ginza.
The drawback; the dollar has hit a 13-year low against the yen, and the Leica M2, for which I am now searching, though abundantly available within walking distance, is usually priced a few hundred dollars above that which I have seen on eBay and at US-based sites. A bit of a Catch-22.
Still, I have no desire to leave this joint! And as Tom mentioned, the Tri-X is cheap.