Macgeejapan, I lived in Japan for two years. I'm now back in Ireland for 5 years. It was a great experience and would go back again if I could get an non-english teaching job. I returned because I was offered a postgrad course that I wanted, otherwise I' could be still living there. If I was you i'd be in no hurry to come back, as 'home' is really where your're the happiest!
Turqoise, why not visit somewhere closer to home and leave japan for another occasion when you have more time. It's a very long flight and it will take 2-3 days to fully get over the jet lag. The benefit of going for longer is that you can make very good use of the economical japan rail pass. Also, Japan is a country where you probably won't get to interact much with the locals (if you don't have the language), unlike somewhere like Thailand. If that's not a problem for you and if money is no object, then go and enjoy yourself!