Go to Niseko. There's like three resorts there all on one pass.
"I don't care what snobby Westerners think. Skiing is whatever you make it, and we try to make it fun. In the East, what else can you do? We ski rails. We build jumps. We'd ski pow every day if we could, but we can't." - Doug Bishop, president, Newschoolers.com
I went to Niseko this winter and it was one of the best experience ever. If you are heading to Japan, I recommend traveling around the country for at least a week, depending on your budget. I will posted more information up tonight, but if you have any specific questions, send me a PM.