Pharrell Williams - producer, rapper, celebrity, one-half of The Neptunes - has an iPhone that's finished in 18k gold. Seriously. He lives in a different world than you and I do, a world where guys named Jacob the Jeweler prep your blinged-out iPhone for you so it's good and ready when the time comes to give up that BlackBerry Curve.
Myself I'm not so into gold, but Pharrell's iPhone is quite the eye catcher. While I have no idea what it might cost to do something like this to your own iPhone, I can tell you that for $150 (the price goes up depending on what options you choose), Colorware will trick your iPhone out with the color scheme of your choice. It ain't gold - it's a high-gloss, scratch resistant finish - but an orange and black iPhone is more my speed than 18k, anyway.
Check out Pharrell's iPhone over on BoyGenius Report or you can design your own color-modded iPhone at Colorware.