Greetings fellow citizens!

Well I had strong determination to wait with upgrading my PC much later, but as SC is making it more and more impossible to resist not playing AC, especially with FPS module coming out soon, and introduction of REC, my resolve was heavily hindered so I went and bought a new rig.
Bye bye 10 min loading screens, and close to 0 FPS, hello smooth game play and moving targets. Not to mention I'll be finally taking a walk in my Connie :)

i5-4690 3.5 GHz
GTX970
8 GB RAM (budget didn't allow for more now)

And now I need your knowledge, and experience. Which OS should I get? I'm reading a lot of good things about Windows 8.1, but I also seem to remember reading somewhere here that it doesn't play well with the Rhino. I had some past troubles with mine on win 7, not that I blame the OS for that, but I managed to isolate and deal with the problem so I have no more issues any more.

1.) Did I buy solid parts, looking at the future of SC? I don't intend to play on 4k resolution, maybe OR at some point though..

2.) What OS would you recommend baring in mind my controller?

Thank you!