Agreed. There is no discernable difference in gaming between either of those processors; http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-5.html
With the PCIe bandwidth available on your board, the 2nd graphics card will make a major frame rate improvement in gaming. Keep in mind, though, that micro-stutter is always a possibility with some games with SLI. Although, I haven't had any that I notice with my 2 570s... which are almost the same as 2 560ti's.
Your other video work won't be able to tell the difference between processors.