I've used Windows, Linux (too many flavours), BSDs and recently found an operating system which gave me the same feeling as the Amiga: Mac OS X.
On the top you've got a friendly face that works brilliantly - intuitively - and underneath you've got a coherent file structure where you stand a cat in hell's chance of understanding exactly what (almost) every file does on the operating system.
Linux has become too fragmented with the distro wars, environment wars (KDE! no! Gnome! Fight!) to the point that it's damn difficult to use as a desktop in my experience. Ubuntu is a breath of fresh air, and I really wish them well as they've got exactly the right ethos, but all the same it doesn't quite do it for me.
The Apple approach of providing end user and power user functionality wrapped up in a cohesive functional environment really enthused me to the point that my next machine will be a Mac. I'm running OSX on a Dell C640 as an evaluation and will be purchasing a macbook once funds allow...
It honestly made me think of the Amiga days and what made them great.
