Hi Dave
Windows 7 leaves Windows XP way behind in every single department.
Windows 8 was designed to bridge the gap between tablets and the Desktop, thus allowing optimum use with both a touch screen and a keyboard and mouse, unfortunately they concentrated too much on the touch screen operation thus alienating most of their Desktop users, however the new team are now starting to fix this with updates, (Currently on Windows 8.1 Update 1) however in truth it will probably be next year before the optimum version is finished. (Code name is Threshold although some have speculated that the final name will be Windows 9, so as to get them out of the mire that Windows 8 got them into)
BTW Windows 8 is the best Windows yet for music, leaving even Windows 7 behind.
As to monopolistic, try Apple, as there systems are as closed as you can get, also support is dropped after about 3 years thus you have to upgrade to stay up to date. (Compare this with XP which was supported for about 12 years)
If you go for Linux, go for the Mint version
http://www.linuxmint.com/ as the usual Ubuntu is just full of bloat ware these days. (I have been using Linux for about 17 years as an addition to Windows; however it is not suitable as a replacement unless you are happy with basic use. (Which to be quite honest covers most home users)
It is also limited with music as there are not drivers available for a lot of popular music software/hardware. (Home or small productions are fine though)
Hope this helps
Bill