I'm lucky that my gray hair (currently colored my "normal" color) is more silver: really shiny and straight. So, when I take the next step of letting it just be gray I know it'll look pretty good. I know a lady here at work who has silvery hair, and it's cut in a bob, and she looks so elegant and classy.
I guess I'm thinking of the, well, kind of hickish women who let it grow and process the crap out of it and it's all wiry and brillo-pad looking, with split ends. Yuck. That's the kind of long hair I would avoid. I can see me being earth mothery when I'm 50. Wait, that's too soon. 55.