Apple's Setup Assistant and it's little brother Migration Assistant are total miracles. They make it easy to set up a new Mac by copying various settings, applications, and data from another Mac. Such a valuable feature; saves users literally days setting up a new computer. I don't think Microsoft's ever gotten this right. I have to think Apple's sold a lot more new computers to users who know the upgrade will go easily.
I like my Air so much I went out and bought an iMac. I needed a monitor anyway; why not pay a bit extra to have a computer bolted onto it? So easy to set up. Plug in my Time Machine backup drive, say "import everything", and I'm done. All the sensible settings were carried over. All my apps. All my weird stuff, like the Canon printer drivers and my personal Homebrew install and the odd hacks that use undocumented APIs. The only thing that didn't just work on the new machine was Xcode; it was all there but for some reason my PATH didn't pick it up.
I realize Macs have been able to do this trick for awhile, but it still seems like a miracle. The new App Store should make it even easier by streamlining licensing. If I understand right, if you buy an app on the App Store once you get the right to install it forever on any of your machines. I hope I have that right; that's how the iOS store works and it's how all my Mac apps so far have worked. That's a pretty user friendly policy, also easy to understand. I wonder how it works in offices?