the 3G and 3GS (the 3rd one) had a polycarbonate backing and came in black or white. they were also available in both 8GB or 16GB models for $500 or $550 IIRC— but you could get them severely discounted if you signed up for a wireless plan ($99/$149). the original model only came in the 8GB model for $500 with no sign-up discounts.