One other essential - make sure you get thee to a karaoke bar. The best thing about them is that they're private rooms, so it's just you and your friends to be embarrassed with. One of my enduring memories of my first trip to Japan is being down at the opposite end of the corridor to the room we had booked, and at a decibel level that drowned out anything coming from the surrounding half-dozen doorways was my husband bellowing 'Anarchy in the UK' into a microphone. Aah, magic moments...