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No need to panic, those "new" things are most likely just panel applets, a bit advanced versions of current ones. If you don't like them you can just remove them. I customize my panels anyway. The default layout is ok but I have my own preferences.
Too bad though, when I first saw the icon and the name of the app up there for a moment I thought they FINALLY made Global Menu Applet work (like on OS X, with the app menu on the top bar). I'm still hoping that's what it is, not a simple Window Selector.
The current preview doesn't offer the ability to turn this crap off, so it's not a given that there will be some way to return to the classic Gnome desktop.
It's beginning to look like KDE4, a whole lot of UI fluff that they know most users would turn off immediately if they could, so they have to force it on everyone to satisfy themselves that it's being "given a chance.
For once I wish they would just copy OS X and Windows.