Is this a good gaming build

Great build but I would go with an H100i for cooling. Also, you might want to invest in the 780ti for a build of this size
 


650W is enough.
750W if you plan to SLI
I would choose a better power supply.
Good brand to buy from is Antec, Coolermaster V series, Corsair (HX,AX or TX series), Seasonic or XFX
 


Corsair is a good brand yes but certain products aren't. like the CX series or the CS series. They use cheap caps and build quality isn't great. They are really budget power supply