I personally believe modesty lies in how I behave and represent myself. I can wear the headscarf and not-too-tight clothes, and yet still be sexually attractive, if I use my gestures to "send out signals", as Bro Emil has put it. Anyway, I find it in many occasions that 2431 works wonder in shunning unwanted attention. When I find some guys "oogling", I just lower my gaze and most of the time, guys will get the "I am not interested" signal and back off.
That being said, I try to dress by taking into account the social values and modesty standards of the environment where I live in. The absolute modesty limit prescribed in the Qur'an is to cover my breast and private parts, so I'll have to say goodbye to clothes with low neckline. Then I will use my reasoning as to how I should dress according to my environment. I live in Australia, so I figure that short-sleeved top and jeans will be okay, and most will not find that sexual. The most I will push it is sleeveless and knee-length skirt (which will be rare, unless the temperature hits 40 degree). If I go to any Southeast Asian countries, then I will set my limit to long-sleeve top and long pants/skirts, because that is what is considered modest over there. But if I go to any Middle Eastern countries, then I will wear the hijab or maybe even niqab if that is what equates modesty for women.
As a woman, I know well what my intention is when I dress. Surely, I know it is immodest to walk around the street in strapless top and a mini skirt (cause most of the time it will turn people's heads). Anyway, I'd love to think I can still dress to look beautiful, but not sexually attractive (but then again, I don't know what men's opinions are).
this makes total sense to me, and i'm the same way...although i stick to long sleeves and jeans.
oh, and i should add...i wore the hijab for over 8 years. at the time i put it on, i truly felt it was required of me because everyone told me it was. i started struggling with it when i got pregnant with my fourth daughter...i found it bothersome and hot. i know that sounds petty, but i'm being honest. i kept it on for 6 more years and two more daughters...yes, i have six daughters, lol...and i decided just over a month ago that i need to choose between fulfilling others' ideas of what is required of me or being happy and fulfilling what Allah requires of me through His book. i removed the hijab and i have to say i'm a much happier, devoted person since. the hijab had become a source of anger for me and that wasn't healthy.
luckily my husband is supportive and understanding...some others? not so much, but that's their problem.