Just a tip: Even if you don't plan to install Windows 10 right away, you should still install and sign up for the "Get Windows 10 thing" so you can at least register your free upgrade. As long as you register within a year of Win10 release then you can choose to install it whenever you want, even after the "free upgrade" period has ended.
In short, registration doesn't require it to be installed, but once registered you then "own" the right to install it whenever you are ready.
Discussions about stuff that isn't Hardware. Keep it legal, or at least vague enough to cover my ass if the lawyers gets on my case.