1. The All New Start Menu
the new start menu is fully different fro the previous versions, and a much more enhanced start search interface
2. Most advanced task manager
The Task Manager in windows 8 is the best one till date... it has several new options like option even to manage the startup items and more than the previous task managers, and a better easy and soothing look.
3. Fully Integrated Cloud Services
Windows 8 is cloud based OS and has a fully integrated cluster of cloud based services supporting uploading of all your files, documents, pictures, address book....and even much more--Supports sync of data within the third party apps.
4. Newly formatted windows explorer
This is not very much changed, but had some adapted look from the MS Office 2010.
5. Metro style apps downloadable from MS Store
6. Automatic changing windows borders in tone of Desktop Background
7. Ultimate Style Media player
The media player seems to be the best metro style application.
8.Window Snapping Feature
Snapping of windows helps to divide the desktop window in 2 parts, the left and right one, and both are independent, seems like stolen from linux distributions but with a different taste