Sakuragicho for live music performances!
I enjoy watching the musical performances in front of Sakuragicho station (in Yokohama which is nearby Tokyo). These performances range from jazz to pop. I find it really entertaining to walk around the Minatomirai area, because there is always a different group performing different styles of music! This was one of my favorite performances that I have seen in Sakuragicho: http://www.youtube.com/watch?v=bWAPCxNo-PU
If you want to watch a live music performance, I recommend going to Sakuragicho at night!