I think the culture isn't the problem in Japan. Sure, it's different but not a problem. Language is the big problem as you need a really high level of Japanese to even be considered for a job. Then as a foreigner, it gets even harder. And English is only known by a few.
Personally I think the Japanese education system have to change to make sure the Japanese learn better English. Japan is seeing more and more competition from other Asian countries (mainly China and South Korea) and the domestic market isn't what it used to be. English is a basic need for doing business on the international market. Some Japanese companies have understood this and are using English as the official language. (One example is Rakuten which sells all kinds of things over internet).
Back to the topic: I think many countries in Europe is good. And as a Swede I have to say Scandinavia! US is good if you get a job in a good city. Australia seems nice
But it all depends very much on what kind of contract, benefits, vacation, salary, etc. you get.
By the way, the best way in to another country is by an Expat contract. Sure difficult to get but once there it's very good.