Being in a City, where the temperature throughout the year is “Hot”, I have always opted for Light Coloured Cars. My reasoning was simple. If you have a dark coloured car parked under the sun for long and then when you get into it, it is going to feel like sitting inside a toaster. Whereas a light car will reflect most of the sun light and you will relatively feel better.
Now my choice is being proved right by a study conducted by an Australian Auto Insurance firm. The study has categorized (in the order) light colours like Yellow, Beige, White & Silver to be safe and dark colours Red, Blue, Green, Black and even Gold as not so safe.