Been researching Weegee's work lately and found out that one of the films he used was infrared with flash (his movie theatre lover shots). I also saw the Japanese photographer Kohei Yoshiyuki's work in Vancouver in the summer which was rather fascinating. I have never been much of a fan of IR film but using it combined with flash at night might yield some good photographs. Not sure I will have time to work on this before this next trip but it might be a technique to consider in the future.
http://jkaranka.blogspot.com/2008/01/how-to-infrared-flash.html
http://flocosemelhante.blogspot.com/