I'm not impressed, not by anything in the keynote. Jobs' MS bashing reached new highs and lows, and it more or less made him look like a moron fanboi. Windows Calendar's "colors aren't quite right"? WTF?!?
The biggest new feature is of couse Time Machine. It's EXACTLY the same thing as MS Volume Shadow Copy (a.k.a. Previous Versions), and it came standard with Windows Server 2003 - we use it extensively here to help avoid having to do long, intensive restores from tape. It's already standard in Vista as well. BTW, it wasn't innovative when MS did it either - it was a standard feature in VMS 20 years ago. And you know, it doesn't crash when using it in highly public situations on ANY of those other OSes, either.

The other "new" items on the web site look to be minor improvements on things OSX is already good at, which isn't a bad thing. The only one that really has a real impact as far as I can tell is Spotlight being able to index other systems. I can see a real use for that, and I forsee it showing up in Vista before long.

Oh, Cider DOES look cool, but you've really got to have a $2500+ MacPro to use it. You can almost build an equivalent gaming PC and own an iMac for that much.