Well, I seem to remember reading somewhere that a study was done where they got people to rate themselves, and then other people to rate them afterwards, and apparently people scored themselves several points higher than the average score that other people gave them. In other words, apparently most people think they are more physically attractive than they actually are.
That said, people have different tastes and thus differing levels of attractiveness towards others, and I'm not sure you could truly rate someone "objectively" because of that. Now I don't think that I'm a bad looking guy, but taking into consideration the aforementioned study, and the fact that I've never attracted a girlfriend, I'd probably say a 4. Otherwise, I honestly think I can look pretty decent on a good day after a clean shave, and I'd like to think I'm capable of a 6... Once again though, apparently we view ourselves as more attractive than we really are. Kind of a scary thought.
TLDR: See bolded font