The superbar!!!
First off, I often browse forums that have "show your desktop" threads when I'm bored. The superbar just looks very "out of place" in all the screenshots. I think this is because it is not centered (ala OSX's dock) and therefore creates a messy layout (I know you can center it by inserting a dummy folder in front of it, but you still have the then ugly start button all the way to the left.)
Also, there is only one style to the bar so far (if you play with the color, intensity etc. you can see a kind of texture to it) whereas OSX has many different styles for its dock, straight out of the gate, and microsoft has a habit of making it imposible to edit such files until some genious figures out how to.
I also don't like the way the pinned icons look when they have something open (the [ ]] effect).
I HATE that fact that microsoft wants to decide what icons we can pin to it. I ALWAYS have the recycle bin on the taskbar, so that the only icons on my desktop is files im working with. This is only possible with various tricks in w7 - none of them produce the result I want (just placing it on the superbar, showing full when full - and empty when empty). And I don't want to use the, in w7, ugly quicklaunch bar (with large icons it makes the bar taller than the superbar with large icons).
I scrapped the new look of the taskbar pretty quickly, and made it look like the standard xp/vista (with small icons) because of this. At least I could still place the recycle bin on the quicklaunch bar then.
I also don't like the look of the start button when running in classic look. They could and should have made a window symbol instead, imho.
The superbar has potential, but only if microsoft makes it possible for the user to do with it what he or she wants.
Straight after installing w7, one of my drives clonks at intervals (w7 polling it or something) while the os is running. I got a feeling w7 isnt really using AHCI in the same way as XP, since - in XP with AHCI, that drive only clonks when booting up the PC - and after restoring the XP image (which I did yesterday because I had to grab something I forgot to place on another drive) the clonking is, as it was before, not there while XP is running.