As a sometimes OSX user I have to admit there are some little things in that OS that I like and miss when I'm using a PC. Expose used to be one (though the new Vista task switcher is cool, and you get some good functionality if you install IntelliMouse drivers), and the Dock was another.

One great add-on for Vista that I've discovered recently is RocketDock - a very capable facsimile of the OSX dock with some specific Vista goodness (my two favorites are being able to see previews of running applications, and set dock icons to open the active application rather than a new one)

There are a number of docklets available to add extra functionality for the dock but the ones I've had a quick play with so far fall foul of the Vista security model so I might have to wait a while until I can move the start bar into the dock.

Ah, I still remember being able to do these things in OS/2 Warp!

Another good Vista task switcher worth having a look as is called Switcher which performs a number of layout and short-cut functions very well, and isn't written from the perspective of trying to emulate the OSX implementations.