Microsoft has debuted its next generation operating system and they've designed a new operating system from the ground up for a cloud-centric world and to provide the best experience on all devices whether that be a phone, tablet, TV, or a full-on desktop.
With Windows 10, the company isn't going to take a step back and rather than introduce a completely new UI experience, they plan to further refine the Windows experience you know and love, but still give you the appropriate experience on your respective device. This means bringing back focus to things like the Start menu and giving you a proper mouse and keyboard experience while still bringing new experiences to touch/pen input. Available 2015.
