The only colors that do anything for me are Black, White, and Red.
Black/White are the classic iPhone colors, since the 3G.
Out of those two, I think I'd go with White because it shows fingerprints less easily, and the bezel is still black. I do notice that the White this year is a bit more of a cream color, and not as pure White. The white on the 3G and the XR was really white.
The other colors are too pastel. Reminds me of the iPod nano 3rd generation colors, even the Product Red is similar, but I do like that one. The rest don't do anything for me.