I personally love the mechitza. (Within limits: so long as I can hear the service and can see the Torah reading.)
For those of you who are unfamiliar with the mechitza, it is a separation between the genders in orthodox (or some conservadox - conservative leaning towards orthodox - services). It is usually very pretty, maybe lace or latticework. However, it can be as much as a thick curtain or be a balcony. (The balcony gets a bad rap, but I haven't found it to be as described - unable to hear or see anything.)
Unlike many converts, my "default" rule is actually the mechitza. And I actually felt uncomfortable without one when I began attending a conservative shul.
There is a halachic/traditional reason for the mechitza: Calm the hormones during prayer services. Most people phrase it as keeping the men from being distracted by the women. I think that a man must have started spreading that rumor, because us women can be just as distracted by the opposite gender! Particularly with such a shidduch crisis going on, the single girls are practically salivating over that mechitza to see if any young single men have wandered in!
I like that the mechitza helps me keep my focus where it belongs: off the men and on the davening. Of course, I still find ways to peek through!
However, there are other very interesting effects of the mechitza. Only the orthodox Jews believe me when I describe my theory, and I've even had liberal Jews be pretty rude and tell me I've been brainwashed. I have not been brainwashed (at least not here), and I promise this is true.
I've found that the mechitza emphasizes our individuality. When I first began attending an orthodox shul so many years ago, I had a very hard time learning the relationships between the people I met. I met many men and many women, but even two years later, I was still discovering who was married to whom! I don't think I ever discovered who all the children belonged to! Because of the mechitza, I was forced to meet everyone as an individual. Only later, at kiddushes and meals, could I begin learning how these individuals were connected.
When I began attending a conservative synagogue, I met people as family groups, and inevitably, one person is naturally the "spokesperson" for the family. I walked away feeling that I had really only met one person, even though I had met a couple with children.
Some people will continue to feel that the mechitza is sexist, but I'm afraid I will never be able to agree with that argument. Because of the mechitza, I've been able to meet each individual on a deeper level, as well as being able to meet more people. Both quality and quantity have been enhanced.