Most software that support GPU acceleration can only utilize 1 VGA, therefor it's better to settle with a GTX780 than both the options above. GTX780 is stripped down from a high-end workstation graphic card also, meaning it will give you greater performance with your pro software than even the GTX690. As for gaming performance, there's nothing to worry about unless you are running a triple monitor setup.
As for PSU, your current one will be sufficient.