A few posts back in the comments section, the importance of eyebrows came up. I'll admit, I like to see a nicely shaped eyebrow. Lisa then likened unmaintained eyebrows to unshaven armpits, and I guess it wouldn't be much of a stretch to add unshaven legs to that as well. Now, the point of all this was, it's true. Hairy legs and especially hairy armpits on a woman are terribly unattractive. There is some leeway for the eyebrows though. Anyways, why is that? Is it evolutionarily favourable for women to have no armpit hair or leg hair?? Of course not, if that were the case, women wouldn't have to shave their legs and armpits. Natural selection would have weeded out the hairy women and women would have evolved so that leg hair and armpit hair just didn't grow. I personally think it's because we (as males) see women on tv, in movies, and in magazines who we are told are attractive and of course, they're all sans hair (and skinny too). We then adopt this notion of what is considered attractive, and it sticks.
This article states that it all started back in the early 1900s with ads for sleeveless dresses, but it also indicates that women have always been fussy about their hair (or men have been fussy about women's hair), it just wasn't until 1915 that women's clothing started uncovering the armpits. I guess by the time a guy got to the point of seeing a woman's armpits back then, he wasn't really so concerned about how hairy she was.
I guess, me personally, look at whether or not a woman shaves her legs/armpits/eyebrows as an indication of how well she takes care of herself. A woman who tries to look 'good' is more physically attractive than a woman who just lets everything go 'wild' and says, "it shouldn't matter". In a perfect world, maybe it shouldn't matter, but it does. Blame it on the media, but clean shaven, 'well maintained' women are hot.