Knitting Frenzy

I am going to knit a scarf for Captain as promised since last year.....
It was such a waste that i left my cashmere yarn and needles that cost almost 100 dollars in total in Australia and now i will need to spend more money on new yarn and needles and crochet hook....

What colour of yarn should i buy? Dark blue？Grey?
I think classic colours will go along well with most clothes that Captain wears.
I prefer ash grey colours for scarves...classy.....