Linux: GNOME Shell
I decided to give GNOME Shell a try.
The GNOME Shell redefines user interactions with the GNOME desktop. In particular, it offers new ways for the user to find and open applications and documents, switch between various activities, and view incoming information such as chat messages or system notifications.To say that I love it would be an understatement. It's exactly the sort of user interface innovation I was hoping would happen in the Linux world. What I like is that it isn't just eye candy. Instead of just being a badly done knockoff of Windows or OS X, it's new, clever, and interesting. It simplifies my desktop, while at the same time making me more efficient and powerful.