[Philip Lelyveld comment; this only covers hardware. I'll post a 'highlights in experience' list separately]
1. HTC and Valve show off the Vive VR headset
2. Oculus unveils its first consumer headset, Rift, and Oculus Touch hand controllers
3. Microsoft shows off speedy progress with HoloLens, its holographic headset
4. Cameras envision new ways to film virtual reality
5. Google Cardboard goes out to New York Times Sunday print subscribers
6. Samsung starts selling its new Gear VR
See the details here: http://www.technologyreview.com/news/544866/the-6-most-important-things-that-happened-in-virtual-reality-in-2015/?utm_campaign=newsletters&utm_source=newsletter-daily-all&utm_medium=email&utm_content=20151221