1. Cortana and the new search bar- Cortana can pull up relevant info for you pertaining to your computer and stuff from the internet through voice or typed in commands. It's a really nice integration of a search/run bar and a tool to use to look things up without actually having to look them up. Cortana isn't THAT useful but its still something nice to have.
Searching is kind of cool, but I want my search provider to be google, I generally find it is better than bing and provides more relevant results. if I want to search on my computer then I want to search only on my computer, if I want to search online I want to search only online.
I have a reason for this, often times in line with the work I do, I may have a document that I remember a small part of, perhaps a device name, IP address, or password. (lets say I recall a login for a router, but can't remember the line provider details), I can search on my computer only for the credentials I can remember, but I do not (under any circumstances) want these details transmitted in plain text out to a search engine.
Conversely, I may have a lot of information about a subject on my computer already. I have access to my well sorted and well filed information, so if I'm searching for information recalling a specific piece of technology (lets say max throughput on an ASA 5520) I don't want all my docs to appear in the search, I know I haven't recorded that before, I just want data from Ciscos site.
2. DirectX 12- If you're not a gamer please disregard but DirectX 12 will enhance performance in games that use it through far better GPU use and greater leverage of multiple threads/faster cpus. The draw call and rendering process has been greatly enhanced, allowing for greater framerates as well as up to 5x more pixels in a given frame. DirectX 12 also adds a low level api so that developers can get better access to the hardware in optimizing the games.
I'm not a gamer...
3. The start menu- Live tiles are pretty cool and their integration into a simple, flowing start menu is really nice. I like it and I think it's very modern.
but live tiles in start menu aren't nearly as good as live tiles on the start screen of windows 8.1,
basically if live tiles are great then they surely deserve proper screen space, not being cramped up into a scrolling menu?
You're forgetting that the camera and the mic can be turned off in settings. I don't have a camera nor a mic on mine.
after accidentally starting video chat a few times in Lync whilst at work, I tend to have a small circle of black tape over the camera, it blends in well with the case so that you wouldn't see it at first inspection.