GTX 1080 or Titan X for video rendering? Are they supported by Premiere Pro and the whole Adobe Collection?
Currently there is a problem with the GTX 10 series drivers. They do not handle R3D media. You just get a blank screen. There is a problem with the nVidia 368.xx series of drivers. If you wait a while until this bug is worked out and some forum members successfully test it out the GTX 1080 might be a good option as it has some great new features.