Ubuntu Windows Wallpaper:
MacOS Unity Theme:
sudo apt-get install unity-tweak-tool
If it fails to run see: http://askubuntu.com/questions/449943/unity-tweak-tool-fails-to-start-with-the-error-com-canonical-unity-webapps-sche
Zukimac Is a Flawless Mac Theme for Ubuntu (If You Like that Sort of Thing)