Got to hear and see the new one. It's slightly quieter...not "whisper" quiet as MS says, and not as quiet as a PS3 either. But the disc drive is still noisy. In fact, it sounds the same if not louder.
I don't know why people are calling it "slim"....it's more like..."short". they just chopped a couple inches off the side (or top if vertical. Still has a power brick too, but it is slightly smaller.
And the internal HDD is removable but proprietary...I suppose you can crack the casing open, but seriously...