I recently picked up a GTX 680 and noticed the same DirectX crash issue that has been noted here. I turned DoF and AO off and I've only had it happen once since then.
I have, however, noticed another issue. I'm not sure if this is specific to the GTX 680, but I never noticed it with my Radeon 5850. I've uploaded a video in the hope that someone might know what is causing it.
Final Fantasy XIV GTX Issue
The first part of the video is the easiest way to demonstrate the issue. As I open and close the menu, it moves smoothly, most of the time. Seemingly at random, you can see that it hangs for a split second.
In the second part of the video, I show it happening as I rotate the screen around my character and rotate while moving. At 40s and 48s in are two obvious examples of the issue.
This isn't something that happens rarely. It happens constantly and is extremely annoying. Has anyone experienced this issue or know what might be causing it?