The interesting thing about the white iPhone is that it's really just the same as the other iPhone 4, but the rumors around it says that it's more expensive and has more functionality. In reality though, it's just a color change.
I'm happy with my iPhone 4 in black, and have dabbled with using different cases that make the back of it white, green, and just about any other color. So, I'm just not sure why there's so much excitement around the white iPhone.
With the above in mind, Palm did create a tremendous amount of buzz each time it released a new color for its successful Palm Centro device, so I'm sure that Apple's white iPhone will create a similar amount of buzz, especially since it has changed its main page to feature it today.