Kyoto and Osaka are very close to each other and offer a nice contrast between the pre-WWII bombing architecture and the modern city. Osaka is a hip little Tokyo, and you can probably find some cool bands playing on any given night. Tripod Jimmy is a lot of fun. Go see them (if they haven't broken up). Lonely Planet is the guide everyone I know used while living in the country (myself included). Hiroshima is great. Miyajima isn't too far from there and is also a nice day trip.
If you like Mariah Carey, you must make a trip to a used CD store. Banana Records is a new/used chain in several major Japanese cities.
There is a northern beach in Bali that has black volcanic sand. There is a certain town associated with it. Spend some time exploring the various places to stay...some are quite nice and quite cheap.
There is an incredibly expensive hotel ($300) a night that sits over a valley a few minutes from Ubud. I believe it's the Alila Ubud Hotel. You will be passing through Ubud anyway, so check it out...you might not want to stay there, but if you go a bit before sunset and order dinner at the restaurant, you will have one of the most spectacular views of the valley. You'll spend $40 per person on a really nice dinner, which is expensive relative to the rest of the island but it's worth it and it's not too crowded...or at the very least, it's upscale and a bit secluded (no drunk frat boys). I sat down with a casual outfit and it was quite alright. I remember that dinner more than anything else about my trip to Bali. For the full experience, get one of the locals to take you on on the back of a scooter to the outskirts of town!