My impression has always been that, for modern equipment, you pay quite a bit more in Japan than in the US, especially since the exchange rates are so bad. Admittedly, I haven't been to the real specialist places, since I wasn't actively looking for camera gear any of the times I've been in Japan.
Vintage gear is another story, though. Looking at reports of the classic camera shows there makes me jealous of how much cool stuff you can get for low prices. It's like a good thrift store find, but hundreds in one place and without the hassle of constantly searching for stuff.