This is the only system I ever use, because it's the easiest for me for "looks." A 1 is someone you are completely repulsed by physically, and a 10 is someone who is drop dead gorgeous. I myself am pretty picky and tend to only date in the 6-8 range because I have high standards yet have problems trusting really attractive women.
Although I have played this points game before, I couldn't honestly explain it to someone. It's only ever something I've done when my friends start. But I did include personality, e.g. 7 on looks but 10 personality. I have also used the how many drinks scale, e.g. "Woah, she's a 7 pinter!" But most commonly the BAM scale, e.g. really hot girl walks by we say Bam! (To each other in recognition, never loud enough for the girl to hear).
I know this isn't very helpful, and I came across as a total meathead but if you ever walk past a guy and hear a faintly distinct "Bam!" you'll understand.
1 = completely unattractive and ugly. Candidate for Extreme Makeover.
5 = not really attractive, but not physically repulsive either. Plain. If they fixed themselves up they could go higher on the scale.
6/7 = averagely cute. Most people fall in this category. They're not smokin' hot enough to have a universal appeal and make everyone want them, but they have some pretty attractive features and are not ugly by any means.
10 = absolute perfection. Okay, obviously nobody is perfect, but you would have an extremely hard time picking out any flaws. These people are usually models, actors, or just really attractive freaks of nature.