My 9 year daughter wore nice jeans and a cowboy hat last Sunday, I wore a suit. We have people who wear shorts and sandals.
That being said, I think one should be modest. The Brittany Spears look is a bit much. Us too. We have everything from what we would consider old line Presbyterian men in suits and women in dresses and hats to jeans and T shirts ( I do not remember seeing shorts )
Most fall in-between..dress slacks and a nice shirt, or casual pant suits for women ...Do you remember that David danced before the lord?
2Sa 6:20 Then David returned to bless his household. And Michal the daughter of Saul came out to meet David, and said, How glorious was the king of Israel to day, who uncovered himself to day in the eyes of the handmaids of his servants, as one of the vain fellows shamelessly uncovereth himself!
2Sa 6:21 And David said unto Michal, [It was] before the LORD, which chose me before thy father, and before all his house, to appoint me ruler over the people of the LORD, over Israel: therefore will I play before the LORD.
I usually wear to church what I wear to work. Maybe a dress or skirt set for Christmas or other special days. I wear nice slacks and a sweater or blouse to work, and that's what I wear to church most of the time. My fiance wears a shirt, tie (usually humorous), and khakis. No one has ever said a word, although I know some of the older women would prefer that ladies wear dresses every week.
I do see girls and young women - even some my age - wearing the most disgusting, sluttish clothes. Really, I don't need to see a thong poking out while a 23 year old C&E churchgoer ambles up for Communion in a miniskirt and tight shirt on Christmas Eve.
It's my belief that God doesn't care if I'm wearing designer dresses or nice business casual-like clothes. If I were being immodest or obscene, that would be a problem. I'm not sure how I feel about shorts in church...something to think about.