Last night I downloaded a load of Apple Mac Icons, plus a set of "grass" themed icons for Mobydock.
Only changed a few icons so far, but it's looking good!
Also I've used an ObjectBar theme to emulate the Mac Finderbar.
Anything that takes the computer away from the stale look of Windows XP is fine by me, and I've got to say, with the Zen Garden wallpaper I found recently, I'm really happy with how my puter looks right now.
I used WindowFX to make the shortcuts transparent, TweakUI to get rid of the shortcut arrows and WindowBlinds to emulate the Mac OS-X Aqua theme.
It's successful enough of a conversion that when we visited Dixons recently, I showed Charlie an iBook which she found strangely familiar!