Windows Phone 7 Series is official. With so much leaked information before the official announcement, we sort of understand that the new Windows Phone 7 Series will work like a Zune. However, it really blows our mind (or at least mine) that Microsoft has taken the pain to redo this OS from scratch. What we will be seeing is a whole new experiences that we had not been exposed to. It is like a rebirth (I hope it is a good one) for Microsoft Windows Mobile.
What you will be experiencing on Windows Phone 7 Series will be 3 hardware buttons (back, start and search key) and 6 different hubs (People, Pictures, Games, Music+Video, Marketplace, Office). This is a new term from Microsoft. They are reinventing the idea that people would want to group similar things together.
For example, pictures will be nice if they are group together with those that you sync on your PC, or those taken with your phone camera or those that were uploaded to Facebook, Windows Live from friends and etc.
Or if you want to experience the Live Event, here is the recorded one. Very informative if you want to know more about the features of Window Phone 7 Series.