My family plays lots of non-gambling card games (pitch, variations of rummy, 8 to 1) and just recently we started keeping score with chips. It works quite well. I like this idea of using chips for monopoly.
I had mentioned this same thing in the Hall of Fame Thread. It is one of the reasons that I think it is impossible to determine a "correct" or a "best" breakdown for a set of chips, because we only use chips for any game that uses money. I find it goes much faster paying rent on the cheaper properties when using chips instead of paper.