Ha! ok! Yeah, all these comments calling for something new and different are killing me.
NEWS FLASH EVERYONE: It Is New And Different! IT HAS A METAL BACK!
Yes, it retains a similar form factor and many of the same details... Ever hear of building brand image or brand recognition? Think about the solid, chamfered sides of the MacBooks. Look at the MacPro. The first iPad had this look and I expect it will return to it. I've said it before and I'll say it again. Apple is a company that hones in on a particular design after thousands of hours of revision and design and engineering refinement. They do NOT design something new and trendy just so it looks new and trendy.
Think of a Porsche 911. Apple redesigns their products to be better than they were the last time. Unlike a pair of shoes or most american cars (Tarus --> 500 / Sebring --> 200 anyone?) which are exactly the same as they were before but just look a little different, Apple tries to focus on real design and engineering issues that push their own envelope rather than pour time and energy into superfluous styling exercises.
At least that's the way I see it. But what the hell do I know, I'm just an industrial designer.