I've lived in Saitama which is about an hour away by train. Day trips were fun, but I don't think I'd want to live there. (Well, I don't want to live in Japan permanently anyway, but if I had to I don't think it would be Tokyo.)
Tokyo is super, super expensive to live in. In fact it has one of the highest, if not THE highest, costs of living in the world. And what you can afford is usually shoebox sized, with tiny-tiny kitchens and barely enough room to roll out a futon. I think Tokyo is a great place to visit and catch up with people, but no, I wouldn't want to live there.