For your information avilash, GTX 780 has a very poor price performance ratio.
The card costs $700 and is around 15% faster than GTX 770 only.
No point of going for it. If one is wishing to invest in that card, its a better idea to have two 770s in SLI for $200 more and get over 50% performance increase.
But even that is not needed here because a single GTX 770 can get you 60+ FPS Ultra on all the games except Crysis 3 which even Quad Titan SLI can't do.
Well, that is not the point, thread is solved.
Oh one more thing, Windows 7 is better, much better in my opinion. I used it for 2 years and I loved it as a general user and an avid gamer.
Windows 8 is too difficult to use and takes a lot of time to figure out what does what (Those four corners).
I am using windows 8 since last 3 months and am stuck with it because I bought it out of curiosity. I regret buying windows 8 and am totally in the favor of windows 7. Faster booting time difference is not much and can easily be resolved by a good SSD (Which is included in his build) which makes time difference negligible.
Sorry if the post was off topic, but this is my last post regarding windows choice. Any other questions and doubts are welcome.