Windows 7 or 8 64 bit for music only

Consider Windows Server 2012, which is server version of Win 8. WS2012 plus the Optimizer results in an outstanding improvement. The interface of WS is just like Windows.

Check out computeraudiophile.com and the jplay forum within the computer audio section.
Note: I don't run JPlay ( for now); just WS+Optimizer+JRiver.