Today in San Fransico Microsoft announced Windows 10.
The under the covers the version is still Windows 6.4 
, marketing wants to segregate from the current Windows experience.
Windows 10 will run all full range of devices from afrom the Internet of Things to enterprise datacenters worldwide (Azure)
And yes the start-menu is back and better!
The familiar Start menu is back, with some improvements, including a space you can personalize with your favorite apps, programs, people, and websites. Disclaimer: Windows Technical Preview may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. Some apps sold separately; vary by market.
Multi-desktop:
You can create multiple desktops to keep things organized—whether for work or personal use, or both. Disclaimer: Windows Technical Preview may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. Some apps sold separately; vary by market.
Snap improvements:
Working in multiple apps at once is easier and more intuitive. When you snap an app or a program, Windows suggests ways to fill the remaining space. Disclaimer: Windows Technical Preview may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. Some apps sold separately; vary by market.
Task-view button:
The new task-view button on the task bar gives you one-click access to all of your running apps and programs. Disclaimer: Windows Technical Preview may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. Some apps sold separately; vary by market.
Windows Store apps run in Windows:
You can now open apps from the Windows Store in the same format your desktop programs do– in windows that you can resize and move around, and with title bars at the top so you can maximize, minimize, and close with a click. Disclaimer: Windows Technical Preview may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. Some apps sold separately; vary by market.
Pin apps in Start Menu:
Pin apps, programs, and folders to the Start menu for fast access to the things you use the most. Apps with Live Tiles will show updates for the people and things that matter. Disclaimer: Windows Technical Preview may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. Some apps sold separately; vary by market.
Tomorow the preview program will start called the Windows Insider Program:
Sign-up here: http://preview.windows.com
And download the preview October 1st!
See the official announcement video wich contains a short demo.
UPDATE! You can now view the recording of the Windows 10 event: