A 1300W PSU would be awesome for efficiency,
Er, no it wouldn't be. Most psus are most efficient at 50% of rated power. Your system will NEVER draw that much. And at idle, efficiency on a 1300W would be awful.
. . . though I don't necessarily need that, those aren't cheap. I'll be using an nVidia Geforce 460, 470, 480, or something along those lines, other than that I have 4 gigs of DDR3 1600 ram and an i5 760. I also forgot to mention, it must be modular.
First of all, you probably are going to want a 460, 570, or 580, or something along those lines. Those will want a psu from 520W to 650W. If you want to prepare for 2x460, 570, 580, you will need 750W to 850W.
So right now, your requirement is for 520W to 850W. It is not possible for us to recommend one without your being more specific.
If you want to stick with your 650W "requirement", you've gotten good recommendations. If you want to use just one 460, 570, then this psu is right for you:http://www.newegg.com/Product/Product.aspx?Item=N82E16817151094&cm_re=seasonic_520w-_-17-151-094-_-Product