There's some unexpected extras, if you resize a window border to the top of the screen or to the taskbar, it maximizes just vertically (kinda like OSX).  Winlogo+arrow keys docks/maximizes/minimizes/restores windows.  Win+space peeks at desktop and gadgets although I really wish you could interact with it, play with a calculator gadget or something.

The biggest downside to this Win7 beta is probably the IE8 build, for something that is supposed to be nearly at RC milestone it runs like crap.  I keep hitting a deadlock freeze, theres tons of render issues, performance is still very bad (cpu usage at idle, lots of memory use).   Hope IE isn't going to delay Win7 ship.  Why browsers require so many resources to render primitive things like text and graphics I'll never know.