I had blue the entire time I had my braces.
I had my braces in middle school and I was pretty shy, so I thought that if I got the same color every time people wouldn't know when I've had an orthodontist appointment. Nevermind the fact that I usually came to school late or had to leave early for the appointments. I don't know exactly why I wanted people to not know when I had an appointment.
Looking back, I wish I has tried out a variety of colors. If I ever got them again, I might start with silver or blue, but then hopefully have the guts to try other colors, and maybe color combinations. There are some color combinations that I think look cool, but I don't know that I'd try (such as green and purple; at most if I tried that I'd get green on top and purple on bottom).