I noticed a co-worker had some cool Mac-effects on his Windows box. He was using ObjectDock, a free utility.
I've tried it on my work XP box and my home Vista box, and it works equally well in both OS's.
Above is a screen shot of my current Vista desktop. I turned off the Windows taskbar and I'm using ObjectDock exclusively now.
It's definitely fun to play with.
The one thing I wish it could do is show the taskbar notifications AND open windows. The property page only lets you do windows OR system tray (notification area)...not both:
As a work around, I added a system tray dock at the top of my screen. You can see it "hidden" in the top photo and expanded below. It will suffice, but I'd like to have all this in the same dock at the bottom of the screen. The ability to add extra docks is part of ObjectDock Plus, which cost $20.