Have to agree with halfwavyhalfcurly on some points, especially about warm skintones and grey not being compatible! I am one of these, and let me tell you, I put on several grey wigs of differing tones one time, when I was first starting to get some noticeable grey hair(late 30's, and this is with being very healthy too)and I did NOT like that at all! Talk about washed-out! But the "winters" and "summers" do tend to go grey gracefully, because of the underlying cool tones in their skin. For me, I do really look better with either a medium copper-brown shade, or a medium auburn mixed with some medium golden brown, with my autumnal golden skintone. I'm what is known as a high-contrast autumn, because my skintone is on the light-medium side, and my natural, non-grey hair is close to black. In fact, before I started turning grey, and I had my near-black haircolor, people would ask me if I colored my hair(which I didn't at the time)because it was so dark and even in color. For myself, I plan on hitting the bottle for a very long time, and I'm 59! All the time, I see warm-toned women who are determined to be grey, and in most cases, it looks unnecessarily drab, and sucks the life out of their skintone. But this is a personal thing!
I saw a book not too long ago, "Going Grey and Looking Great". It had some good tips, but it seemed that most of the people, including the cool-toned people, had to wear alot of makeup to compensate for that grey hair, IMO. For us warm-toned people, a perk-up with the right color really brings our skintone to life, and we end up wearing less makeup.