The other thing I like about OSX is the "instant on, no fancy flickering" way in which a Finder Window appears. On Windows (Vista, which I checked last), when you open "Computer", there's a green scrollbar on the top that races from left to right, flashes green when it's complete, the cursor turns from a normal one to an hourglass, the icons flicker, a "refresh" happens, the hourglass appears next to the cursor---all this gives a "dramatic" effect as if the computer has done an incredible amount of processing just to show the "Computer" window.
On the other hand, if you contrast it to what happens on OSX, the screen "just appears" without much fuss. This actually reduces distraction (at least to me).
To me it gives the feeling of the Mac showing "real things" whereas Windows is showing some illusion, an abstract representation. Of course they're both just representations, but the Mac's solidity helps me forget that.
I think you're spot on when you mention the impression on Windows of the computer having done a tremendous amount of work just to put up that Explorer window. I note that I "irrationally" try to avoid having the computer do unneeded work — for example, if I accidentally kick off an "ls -lR" against the wrong directory, I jump to hit control-C as quickly as I can, even though I know full well that no harm beyond an infinitesimal fraction of a cent's worth of energy usage and wear & tear would be done by letting it continue to run for a few seconds.
That might just be your computer (or Vista?). On my netbook, on Win7, none of that happens. The only thing I noticed was a slight delay when the Start menu closed and I saw an empty desktop for a split-second before the Computer window Aero'd into existence. The filling of the window was also slightly asynchronous. No progress bar, cursor change, or icon flicker though.
On the other hand, if you contrast it to what happens on OSX, the screen "just appears" without much fuss. This actually reduces distraction (at least to me).