Besides the obvious Ti, copper and even stainless steel lights (I don't own the first two yet, but do like them), I think the color does suggest the seriousness of a light. i.e. A pink colored Surefire/HDS Clicky or Haiku would look kinda weird, but a cerakoted orange Surefire/ Clicky would look more like a though survival/rescue light.
I personally prefer my lights in neutral colors (black, grey, semi-metallic or the previous mentioned Ti, Copper or stainless steel). A nice cerakoted white or orange light would also be nice. I'm more interested in the beam pattern, output, runtime and UI then in bright colors.
I do own a Thrunite Ti in red (almost pink in certain light conditions) and blue. Both nice lights, but the feel is a bit different, though for keychain/EDC backup purpose I kinda like it. My girlfriend however has a purple E05 and a green Ti, because she is more into looks over purpose (though she does admit the lights are useful).