Get Windows 8 64-bit OEM.
1) As said, you can MOVE to a new machine. I did in fact LOOK THAT UP MYSELF.
2) Windows 8 is better in many ways EXCEPT the new interface.
3) The new interface can be avoided with a program like Start8 for $5.
4) New features are going to be Windows 8 ONLY in the near future for Windows AND other programs. For example, Shared Tile Resources via DX11.2 is likely Windows 8 only.
I know many people have been saying "avoid Windows 8 because blah blah blah..." well I've been using it for over a YEAR now and it's the most stable Windows I've ever used. I avoid the new interface with Start8 but I have been playing around with the new interface periodically and there are things that I'm interested in.
There are some very important features such as UEFI security (with UEFI compatible motherboard) which can prevent boot-time viruses such as key-logging software that can record every button you press. W8 + UEFI has a way to prevent this (must install Windows as UEFI not in legacy mode).