If someone was buying me one as a gift, I would get dark blue. That said, I own black, because I found a very nice lightly used black one for very little money. And then laid out $$ for the top hat. Which sadly will likely collect dust in the closet even though I hope to be back in the PSG ring this winter.
I think that there is something just a smidge "softer" about the dark blue; or even some of the more creative colors like a brown or gray that you see the Europeans wearing.
We don't get less brave; we get a bigger sense of self-preservation........
As I put the Dork in DDQ: Dorky-Dressage Queen, my navy tails (from www.rjclassics.com) have interchangeable points, which I can make yellow or a lighter blue, to match the navy helmet and the navy boots. Yep, Dork. The RJ coats are STUNNING, really really lightweight, and under $500. Really!