A very well tailored charcoal suit with a solid navy blue or dark red tie tied four-in-the-hand, white shirt, and black shoes was my go-to. For very cold weather I have a black RL overcoat that I could swear was made specifically for me. I sometimes wore the vest that came with it. I got complimented frequently by people at my interviews when I wore the vest with the suit; apparently it is uncommon in the good way.
I think more important than the color is the fit of the suit and having just the right amount of personal touch.