In Japan, everywhere and anywhere during winter (usually end of November- start of January) everywhere you can find Christmas lights displayed.
Most people don't put it on their house, however it is safe to say every mall, tree downtown, important building will be plastered in lights that we call in Japanese, Illuminations.
There are usually events that go on in designated areas where you can go view them. It is considered almost like a festival and some of these hot spots attract hundreds of thousands of people.
Luck thing is most of them are free to go and see (I wonder who sponsors these things?)
They seem to get better and better every winter as competition grows.
There are even places you can go to see water light shows, laser shows, fireworks, ice skate shows and light "plays" on movie screens. It can be really fun.
So if you are a person who is interested in such a thing you will really love Japan in the winter time. Don't forget to bundle up though, it can get VERY cold in the winter here.