Yuck, I do not like chocolate candy . . . but I do have a favorite color M&M. It was that light brown one they discontinued back in the 90s and replaced with that stupid blue one. I prefer colors that actually look like what you're eating. With the blue, it makes you think of Windex or something.
I actually don't know. I don't eat them enough to know and I went through a few years without eating them at all. I almost want to say yellow, but I'm not sure.