I'm thinking of getting a White and Silver iPhone 5 on Friday. Will it scratch?

Both are using aluminum backings... aluminum is a very soft metal.

From my experience with the original iPhone and my Macbook Pro, the metal can scratch, especially if you have keys rubbing against it.

Couldn't say! 😀

I ordered a Black/Slate color.

I have a black iPhone 4 and wanted to go with a white iPhone this time around, but I wasn't really too thrilled that I couldn't find many photos of the White/Aluminum version on the Apple website, and from what I saw... in my opinion the white and silver clash a little, so I decided to go with the Black one.

If you're not in a hurry, I'd try taking a look at them at the Apple Retail Store, i'm not sure if they have any on display yet or not.

The color that suits YOU best. If anything, the black/slate will show scratches at least as much.