Modesty is a culturally defined parameter. As believers we are commanded to dress modestly (always not just in church), but the fact that nowhere in the New Testament is a list of guidelines given about what makes something modest should clue us in to the fact that it varies by culture. And by the way, we don't have any idea how much skin the clothes made for Adam and Eve actually covered.
A few examples of different cultural definitions of modesty:
Some tribal people in tropical climates where no clothes at all or just loincloths, are we to conclude that the entire society is immodest and immoral just because of this, even if they clearly have marriages and the idea that marriages are to be honored?
I'm living overseas right now, and in the country I'm living in see through tops on women are not considered at all immodest, though I would never consider them modest.
In some parts of Africa a woman's legs are considered the sexual part of her body, wearing shorts would be immodest but covering up up top or not is not a big deal.
My personal comfort level is keeping shoulders to knees covered in clothes loose enough that people can't count my fat rolls, but if I were somewhere where all of the other women were covered to the ankle, I would do my best to conform.
Modesty or at least appropriate clothing is also somewhat situational. My swimwear would be considered modest by any Western standards, but I'm not going to wear it to the mall to go shopping in or to church. Similarly a guy mowing the lawn or doing other outdoor labor can be shirtless and not be immodest, but he it wouldnt be modest to go to a restaurant shirtless.
So let us be guided by personal conviction, honest feedback from one another, and the desire to to whatever we can to keep another person from falling into sin.