I second, or is it third now ;-) the XFX 550w. Solid PSU and can usually be found at a really good price.
EDIT:
Hang on......the CM GX 750 has x4 6+2 pin cables.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817171053
6+2 basically means it can be a 6 pin or an 8pin, just detatch the extra 2 if you need 6 pin, or attach them if you need 8.
Your PSU has 4 of these cables, and you only need 2 of them for the GTX 460. So basically, yes, the PSU you have is perfectly fine for a GTX 460.