I think the white looks gorgeous naked. But I don't like the look of it in a case, at least the cases that the majority of people choose.
However, my daughter has a white iphone, and her case is very sleek. It doesn't add an width to the phone, so I like her white phone.
Since I will use a case, the color of the phone is rather immaterial. Not much of it shows. If I felt comfortable using the phone without a case, I would purchase the new champagne color. Since I don't, it will be black. The black case I use has a black perimeter, so from the front you can't even tell it has a case on it. The black recedes into its surroundings, so it doesn't attract a lot of attention. That's a big plus for me.
A white phone in a "fat" case just looks sad to me. My opinion only.