Shibuya is a great place to visit in any ways!
There is the famous crossroad in front of the station, which is really fun to walk through or for making some excellent pictures.
And if you are getting bored of the crowds and want to take a rest, simply walk to the Yoyogi Park.
I think it is the biggest park in Tokyo and also very beautiful. There are even some small lakes inside of it and it is one of the few parks in which you are allowed to walk on the green area- Perfect for a good picnic!
Shibuya, Tokyo's Youth Center