Luggage and bags:
Make sure to get a small pocket Japanese-English dictionary if you are travelling in Japan. Most of the people living in the province or the outskirts of Japan don't speak English at all!
The map is also a good thing to pack. If you don't have any, it is best to stop at any Information Center. Most of the guides at the Info Center can speak English and the maps are free!
Clothing/Shoes/Weather Gear: Bring jackets in Fall and Winter time
Toiletries and Medical Supplies: There are many stores in Japan that sells toiletries. There are convenience stores.
Photo Equipment: Bring a small one. The Sony Cybershoot is really great but make sure to bring your battery charger and have the converter, too.
Camping/Beach/Outdoor Gear: Not applicable
Miscellaneous: Not sure.
Miscellaneous: Unless you speak Japanese it can be a pretty bewildering place! A smile and a point goes a long way and we did learn, hello, goodbye, please,thankyou, 1-2-3 and beer before we left but sometimes a phrase book can be a great help, ours was!
I'd like to thank Mdchachi the info he gave me about Tokyo, which let me correct some mistakes on this page.
Please, take a look at his Tokyo page
Photo Equipment: All rooms in Japan has the same type of power outlet. 2 vertical type (see pic) with additional type in the toilet.