I love Japan, I wanna go back there! *join-ness*
As to where I'd go, I want to go back to Takayama (not as dadblamed humid as the rest of the nation), Kyoto (VERY humid. If you can avoid it, don't visit in July-August), Tokyo, and Hiroshima (special memories for me). I also want to visit Okinawa, some personal history there and it looks beautiful and somewhere up north.