I just got back from 9 days in Japan, it surprised me with being so cheap (anything is after living in Denmark) but people always seem to mention that about Japan before anything else, even in Tokyo it wasn't as expensive as London (accommodation can be pricey depending on location). We stayed in the Remm Akihabara which is on top of the local train station. All train stops and maps have English translations, even out in the sticks and the people are always willing to help but seemed very shy about using English (even the hotel staff) but you will get by easily.
I must have been to the Yodobashi and Map Camera stores 4 or 5 times, its really something special to see if you are a tech nerd, I ended up with a lot more bits than I expected due to the prices (Australia was cheaper for cameras oddly, might be the exchange rate again).
The JR rail pass pays for itself quickly (even using it Tokyo - Kyoto - Tokyo means you break even) and I used MAPS.ME on my S5 for offline maps (Google Maps wont allow you to store any of Japan offline) it was really useful on a number of occasions but sadly lacks walking directions at the moment.
It took me far too long to visit Japan, my advice to those thinking about it, just go! Don't wait!