Check out Shinjuku golden gai area if you're looking for something more than just a bang. It's pretty gaijin friendly, the buildings are old and neat, and the people I met were extremely friendly. I was really drunk there but I had some amazing drinks, I swear. The two bars that I can tell you by name to specifically visit (because i saved their matchboxes) are Zucca and Brian bar.
Zucca was ran by this cute middle age Japanese lady who gave my friend and I this lotus root dish she made. Totally out of blue, free, and delicious. Brian bar is ran by a Korean guy who spoke English very well and was a pleasure to converse with. There was another place that served the most amazing cocktail I've ever had (something with green tea) and I really wish I could remember the name of that place but the only thing I can recall about the bar was that they had currency and pictures with people from the different countries that visited.
Seriously, the best night I had out was when I was bar hopping there. No touts, great people, and great drinks. Thinking about it always makes me smile and I can't wait until I get back in Tokyo next month because my first night will be spent there.
I guess if I had to be level headed and offer some cons to the area, it would be that some places have a coverage charge and it can get pretty cramped in the bars because they are busy and small.