When I bought my car on the last day of Cash for Clunkers, my choices for cars in my area equipped how I wanted were down to two: one was black, and the other was white.
I'd never had a white car, but I have had a few black ones. I chose the white one. White wouldn't have been my first choice, but I didn't want black either. Black looks dirty unless it's straight from the car wash, and you really notice when they could use a wax job.
Now, I picked based on the relative appearance of cleanliness, and I'm not unhappy there (never looks perfectly clean, but it never looks very dirty either), but the thing I noticed right away was that the interior stays cool in the sun.
Even silver and beige heat up a bit, and dark blue and black are positively unbearable (to me) in the summer. But the white car seems to shrug off the heat quite well, and I like it that way. I'm a convert.