Not that I totally live to talk about hair or anything, but...
There is a correlation between the changing color of one's hair and one's complexion. Skin color softens as we age and goes better with greying hair. That's why you often get that "shock" of contrast and know when someone has hit the (dye) bottle a little too hard.
For guys, I think there are basically two ways to go if you want to color. Either go to the salon and get subtle highlights from a pro, or punk out and get an obvious dye job - think Billie Joe Armstrong - and rock your new fashion statement.