I really don't like the look of that Home button, and I hope Apple loses their obsession with "Thinner & Lighter" on their phones.
If it gets too light it'll just feel cheap, I'd prefer to have the thickness of the iPhone 4 and have a better battery inside.
I do love the idea of a bigger screen though.
I vaguely recall hearing that the elongated home button would be touch-sensitive. It may provide a fast way to swipe between apps using nothing but the home button. I think that would be quite amazing.