Salaam all,
I am sure that you have all read Joseph's article regarding covering.
Taking all the verses into consideration, I hold the view that the hair is part of a woman's zeenat and should be covered..not strictly every strand though and not only with a headscarf as hats would suffice too.
In order to take into consideration the many different cultural dresses, the Quran doesn't stipulate a particular style of clothing.
So what I understand is that the clothing should not be tight, arms and legs should be covered but 3/4 sleeves would be acceptable too. A must would be some sort of additional covering for the bosom. Also if you were to wear western dress then long tops that cover the bottom would be required in order to fulfill the instruction and jeans etc should not be tight fitting.