I dye mine. Dying makes my hair LESS unruly, though. 
And I feel better when it's dyed. The dull iron grays made me look washed out and ill even when I had a tan! I tried letting it all grow out and the look and feel of it made me blue. So DH said go back to dying it. I'm close to the color my hair was in my 20's, and I like it. I do mine every 6 weeks since mine is slow to grow and only the grays look out of place. I do it at home, so it's not that expensive.
If mine was a pretty silvery gray, I'd probably leave it alone. I'm usually a lazy no make-up no fussing kind of person. But my grays are dark & coarse, and the damage done by dying them actually works in my favor. Go figure!