Sorry, late to this thread...
Before I would build anything, I'd compare what you have to what these guys are selling:
http://www.digitalstorm.com/vanquish-7.asp
If you scroll down to the bottom, you can see their 1060 gpu PC is priced at $1,199. Yeah, I know it is $160 more, but, it could save you some hassle. Not sure if you really wanted to build a PC. If you like that stuff, then go for it! (Me, I decided a long time ago that I was through with that...).
Edit: btw, do you already have a copy of Windows? If not, how much is that costing you?