Hi,
Its a somewhat difficult choice, the recent offerings from Microsoft are such utter pigs to use, or thats how my (programmer analyst) daughter eloquently put it; namely the ribbon interface & as you state, the requirement to have an account with Microsoft, new ways to do familiar tasks (should be familiar ways ot do new tasks) I could go on...
At the budget end of the market, the hardware dosnt seem to last too well, MS software seems to beat the hell out of hard drives unless you have 16Gb of memory - borne out by the all too numerous HDD failures I replace with the "but Ive only had it 18 months or so" ringing in my ears on a regular basis.
Of the later versions of Windows, Win7 is perhaps the best - I really mean least bad. However, you can install 'Classic Shell' (Google it) which is quite nice as it provides a Windows desktop interface of your choice, including Win XP.
Annoyingly, theres bloatware of very limited ability to get rid of with a new PC, just hose the lot. The very useless McAfee antivirus is thankfully no more, but I suspect theres plenty of desktops heaving with it, best un-installed to stop the nags & AVG or ESET NOD32 used. Demo versions of Microsoft Office can easily be removed and replaced with Open Office or Star Office. Microsofts OOXML format is broken by design, to be honest I'd rather daub dung on the wall with a stick than use Word.
It may be an idea to at least try Ubuntu Linux as one poster suggested, its not bad & certainly much more secure than any PC based operating system.
You could try a Mac but will probably be put off my initial cost, but through life they work out more or less the same, certainly a lot less hassle, the later versions of OSx are somewhat 'commercialised' I prefer Snow Leopard as its lean and very fast.
Ive found Macs a lot more reliable through life, my first 2006 MacBook remains in daily use as does my 2006 Mac Pro which is still blisteringly fast & the software reads most MS file formats, docx etc. The only application I need XP for is Access as I program databases & wrote my company financials on it in '98 it so I run it in a Virtual Machine under VMWare Fusion which is pretty flawless.
As for "so that I can retain my autonomy from the all seeing eye of the MS network." you'll need some software that denies outgoing network connections, I use little snitch & a hardware firewall to deny connection to anything I dont approve of, including Microsoft & a host of others.
Good luck with your search & Im sure it will all be fixed in Windows 9 !
Just my thoughts