In3rt1a :
I recommened an hx 750 because it is the psu I have and currently is just as expensive as the 650 model, so why not have the extra power?
As I have mentioned in my earlier post a very good quality seasonic 620W psu is available at 79.99 dollars from Amazon.com. So, its much less expensive than HX 750.
Again, there's no harm in having some extra power if you can afford it but it should come in use in the future. For that its better to get a 850W so that you can SLI another 770 in the future. Getting a 750W serves no purpose and a PC with a single 770 will not perform any better with a 750W than a 650W. They will perform the same.