I've often pondered this question myself. From my own observations as an inveterate chart watcher, sometimes it behaves like money and sometimes like a commodity. A conundrum.
For some clarification on this Mick Shedlock has written a great article on this topic, check it out:
Misconceptions about Gold
The obligatory chart shows the August contract caught in this downward sloping channel with little swing trades possible of the declining support and resistance. In the absence of any meaningful trend in the bigger picture, this is my preferred way of playing Gold at the moment.