I've come across all kinds of natural but strange colours in my hair. I've had white hair since I was 9, but I've seen brown-red, beige-brown and checkered (ones that alter dark-white-dark-white from root to tip).
There are also two very faint natural streaks at my temples... and I don't colour my hair. I haven't since 1997 anyway. I had slightly lighter brown highlights put in and that was the biggest waste of $60 I had ever spent. I paid $60 for something that just plain made no difference.
But hair colouring might become a way of life for me in the not too distant future. I take after my Dad's family with regards to hair (colour, dental floss-like thickness, huge number of follicles per square centimetre of scalp). My 姑媽 (Father's elder sister) said Dad was born with a piece of white hair. 姑媽 was salt-n-pepper at 35-40 (which is not that far off for me) and was dying her entire head by then.
And I hear (from Mother-in-Law) that it's harder to hide grey with straight hair. *sigh* I really don't want to perm my hair... =P