so far the theories that have been advanced:

intelligent women = more attractive than stupid women
brunettes = more attractive than blondes
public school girls = more attractive than private school girls

i agree with #s 1 and 3, and generally, i assume women of all hair-color are equally attractive, though i do think redheads are especially beautiful.

and in the interest of ego, i will propose:

taller girls = more attractive than short girls
blogging girls = more attractive than non-blogging girls
liberal arts girls = more attractive than e-school girls (but overall, poorer)
which might go against a theory that
rich girls = more attractive than poor girls
(and i have to add a disclaimer that i have many short, non-blogging friends that are very beautiful. so i guess they're the exception to the rule. or whatever.)

this could get more and more specific and go on forever (girls who wear gap jeans = more attractive than girls who wear levis) so i'll stop.

just read, also: "Diotima, Dan Moore and Tyler Cowen all point to a study showing that when they are particularly fertile, women are likely to rate other women as less attractive. Nature concludes that this says something about the use of cattiness as a competitive tactic. Maybe."

yay for cattiness! but i don't understand why it would matter what other women thought of other women's attractiveness when they were trying to get pregnant. unless it gives them a super-boost of ego and confidence and they can just strut their stuff all over the place and get their man. or something along those lines.