It is so true -- there is nothing like black (or maybe darkest ink) for instant chic. I will never rule it entirely out of my closet, for that reason alone!
Brooklyn, it would be really interesting to do the colour analysis, although honestly, a lot of the people who do it are half crazy, in my opinion, and when they start preaching about near invisible distinctions and don't see colours in relation to one another, I tune out. I do think a general sense of whether warm or cool colours look best can be really helpful. Once I ruled "warm" out of my closet, it simplified my buying. I started looking for the cool colours that I liked best, and ignored those that don't appeal to me.
But with the grey hair, there are absolutely changes -- more black, white and grey (which I always wore, but I will wear more of, now). More reds. (Again, I have always loved red but don't wear it a lot). More deeper colours and fewer pale ones -- even chambray blue is "iffy" now, when it used to be the one pastel that really flattered. It's too "dirty" and light now and the combo is a bit deflating, I think.
Lisa, I think you are 100% right about the grey/ black issue in winter for me. It is all about feeling overwhelmed by all the grey around me. If I lived in the 'Peg with its bright sun and blue skies, I am absolutely sure I would want to "tone things down" a bit with sophisticated neutrals! As it is, I do wear a lot of navy and charcoal in winter and will probably wear even more of those now with the grey hair -- but I think I will also look even harder for bright scarves, coats, gloves, bags....
Interesting what you say about grey and your darker hair -- I felt exactly like that when I had red hair. I didn't like charcoal or black as much on me as I did with blonde hair. Suddenly, chocolate browns and all plums, purples, purply-pinks and aubergines (and greens) became intensely flattering.
That is why your outfit the other night was such genius. You had the greens and pinks that are so flattering to your hair, lips, skin, and eyes. You also had the black, but it "popped" against the white, making everything both soft and sharp -- a really nice combo.