Definitely popped is the way to go... some brands are better for it than others though. I find that my Burberry and Lacoste polos are too soft to properly hold a pop. Vineyard Vines and Polo work pretty well though, and I actually prefer the fit of them (yes the CHEAPER polos) over my more expensive ones.
Nothing makes me happier than wearing a white A-line skirt, a nice polo with the collar up, Rainbows, and some oversized white sunglasses. That's KY preppy for you.