For "power users" the fastest and bestest one I found earlier was the right-click on the lower left hand corner "Power Menu" with shortcuts to all the stuff like Control Panel, Power Options, Disk Management and the other goodies.
Some new keyboard shortcuts as well, there's a comprehensive list at:
Aside from that not much going on yet. I spend 99% of my time looking at the Desktop anyway so, I don't notice much difference between 8 and Windows 7 at this point (and yes I ran the DP for some time as well).
I know most of the Metro apps are previews so I hope they get around to adding some features to Reader - having PDFs load to fit the screen and no zoom functionality is a pain in the ass with some PDFs I have. Most typical PDFs will end up not displaying well enough to be able to read (I'm on a 1280x800 screen) well.
Fast, smooth (had to hit Windows Update to get the updated Intel GMA950 driver of course, prior to that it was sluggish), and working well so far on a ThinkPad T60 with a Core Duo (not even a Core 2 Duo).