VR currently has issues with SLI, so don't jump the gun too early on that second 980Ti or you'll be pissing money up against the wall.
VR is the only way I'll go back to PC gaming...that and a powerful console-sized box. Until the quantum leap from 1080 to 4K gaming really hits its straps (Ultra should be the 4K default on PC, not Medium) and VR tech matures (if it matures...), I'll stick to the shallow end of the pool and keep on console gaming.