{New Build} My Preliminary Gaming Rig Components - Advice Appreciated.

Case: Thor V2_______________$130.00___ 10% http://www.newegg.com/Product/Product.aspx?Item=11-147-...
Motherboard: Asrock Extreme 4 $135.00___ 10% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
GPU: Gigabyte 670___________$390.00___ 30% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Processor: Intel i5 3750_______$230.00 ___18% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
RAM: Corsair veng. 2x4GB_____ $52.00_____4% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Power Supply: Corsair 650W___ $120.00____9% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
DVD Drive: Dvd burner________ $20.00_____2% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Heatsink: Noctua Nh-D14 ______$81.00_____6% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Hard Drive: Seagate 3TB______ $140.00___ 11% http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Total:_____________________ $1,298.00__100%

I need to know a few things before I purchase these components. I am willing to swap components out if you can find better (cheaper) alternatives.

1. Will the Noctua not obstruct Thor's top case fan? (would be a big issue)
2. Will the Noctua not interfere with the case's airflow badly? (I prefer full cases for that reason)
3. Will the Noctua be able to fit comfortably on the motherboard (fans orientated to exhaust heat out of the case's rear exhaust) and not obstruct the rear case fan?
4. Would you recommend anything else besides the Noctua? (I will be overclocking)
5. I may purchase a second GPU, will 650W be sufficient?
6. Would you recommend any other case?
7. Will I need any additional cables? (will be getting a Y-splitter for the heatsink)
8. I am concerned with the number of fan headers on the motherboard, should I plug some fans directly into the PSU or invest in a fan controller?
9. Is there anything essential that I'm missing or need to be made aware of?
10. Should I buy Arctic Silver thermal compound for the Noctua or just use their brand?

It should be known that this will be my first time building a Gaming rig, but I'm confident in my abilities to put everything together. I'm not confident, however, in my abilities to pick out components and to make sure I will have everything that I'll require to build this monster.

I'm building this PC because I recently bought Far Cry 3 only to find out I could barely run it on low.
My budget is somewhere between $1200-$1350 USD. The less money I have to spend the better, so if you can cut the cost of some components I will be grateful.
(Already have other components for the system. e.g. mouse, keyboard, etc)
Monitor Res: 1920x1080