Couple of things that need clarifying, to be able to assist. What monitor are you intending to use, and what specific software are you using for "movie rendering" (can restrict choice of graphics)
Personally, I wouldn't be in too much of a hurry to use Windows 8. Apart from use of touch screen monitors, I've yet to see anything to justify it, over Windows 7. Still, it's early days, so I may be proved wrong.
The Sabretooth is an excellent mobo, in terms of quality and robustness, but it is a lot more expensive than some equally capable boards. Of course, if you are happy to pay more for the "quality" of Sabretooth, that is your choice. Having said that, whilst they will work together, the 2600K and Z77 are not the ideal match. I would suggest the i7-3770K is a better match for that mobo, and will give better performance, unless you have a particular reason for using the 2600K, in which case, the mobo could be changed. You need to be careful exactly which RAM you choose, but if you can clarify above points, we can advise on all those points.
Obviously, what you do in relation to operating system. You should get the Professional version, of whatever. Personally, I wouldn't go near Windows 8, for at least a while, but that's your choice. The i7-3770K, is the better option, for processor, so suggest going with that. As regards dust, I'm not really sure Sabretooth is THAT much better than anything else (decent). The answer, really, is a case with decent filters, that you clean/replace regularly; plus a ventilation system that keeps a positive pressure in case, so dust doesn't get sucked in by other routes. As to graphics, 3dsmax uses CUDA, so you should use nVidia based cards. To get that, and gaming, you should be looking at GTX660, up. Obviously the higher, the better will be the gaming experience (one of the reasons I queried the Sabretooth.) You have a reasonable budget, but every Euro saved (sensibly), gets you towards the best gaming card.