Thanks for reading this. First of all, I recently posted a build over the summer asking for advice. I am now much closer to actually building this PC, yet I'm sure some of the parts are outdated or there are better options now available. The only significant change I have personally made is the case and the graphics card (from the 670 to 660Ti).
Here it is:
It looks like you probably won't need to 'update' your computer at all, because your computer's parts are really good. Although, if you're willing to run some of the most demanding games on your PC, I would advise you to change your video card, from a 660Ti to some other Nvidia card, such as 670. But as you stated, you changed between then already, so it won't be needed. But know that the 660ti is powerful, but I'm not sure if it can run BF3 on Ultra, with Max AA with average 45 FPS.
I'd also change your OS. Really. Windows 8 is a pretty new OS, but, well, as any other program, it may have problems while running certain games, like Sleeping Dogs and Hard Reset. I readed some article some time ago, and it had compatibility problems, but it's probably fixed by now. The performance difference of both Win7 and 8 are just of 1-2 in most games, so no worry.
You said that you wanted a good and updated PC, so Win 8 is better for you.