Shibuya is the best spot in Japan. Probably one of my favorite in the world!
Though Shibuya is awesome if you like busy places. It's where all the action is at!
Shinjuku is close by but it does get a little seedy in some parts at night. Though it is still safe.

In my opinion I would def chose shibuya over anything!

With Shibuya you can WALK to harajuku as well