I don't know why everyone always thinks you need a case or a screen protector for the iPhone. I've never put my iPhone 3G and it only has some tiny scratches that you really have to look for. Why not enjoy the phone the way it was designed and if it gets so many scratches that it's unbearable then put the case on to cover them up.
That's good for you... Keep in mind not everyone is like you, and some of us are hard on gear. I have never had a phone in a case until my 1st Gen Iphone, and every single one of them has met a lovely death! I punched the screen out of my first one, dropped the second on the ground rendering it slower then walking to a pay phone to make a call, then ran it over in my car on purpose. I accidentally had the car door shut on a phone and it snapped clean in half. I have had 2+ phones die to cracked screens from normal use and drops, one of which I also dropped a cigarette cherry into my shirt pocket while at work and burned a hole into it, after the cracked screen that is. That one was a trip. I rocked a cracked unreadable screen on a smartphone with pass key lock for 8 months! I shattered a blackjack 1 into too many pieces. I treat my phones like consumable commodities, like they are.
I have had my Iphone in a case from the day I received it, and up until a few days ago, only had minor back scratches from the slider style case. I was lifting a keg for my sister with the phone in my pocket naked, and I managed to press a minor dent into the back on Monday. I take them to junk yards, work on my cars with them in my pocket, hell I don't even worry about them in my pocket when it rains. It's just a phone, and due to the case it is the second longest lasting phone I have had, and the only one to sustain no real damage in 10+ years of damaged phones.
I grabbed a white 32g and I am putting it in a Reveal case when it arrives tomorrow. What the hell I'll try the penguin look (I am partial to two-tones anyway).
Oh and the black ones crack just as much, you just cant see it as clearly as the dirt that gets in the crack doesn't make the crack any darker on a black phone. Go look at all the 3g display phones closely at an Apple store. I looked at 8+ and they were all cracked, both white and black.