Basically, what it comes down to is that we would need an eye tracking VR experience, not just head tracking, to make it useful as a screen replacement. Of course, I see the day when very high resolution small goggles would be something you put on and use in combination with your phone as a laptop replacement. Kind of the Ubuntu idea of a phone that can run desktop software. But that's different from VR. High quality goggles and AR is the future. VR? Not sure, the application is just too narrow, and from my conversations with die hard gamers, many of them just don't really like it for now.
It's worth noting that I think trying to approximate current desktops or monitors in a VR environment is entirely the wrong way to go, as it's an abstraction of an abstraction, when we now have the ability to get closer to the source that the initial abstraction ever could.
That is, we have multiple windows, or multiple displays with windows to approximate our ability to have multiple things in front of us. But we don't actually look at both things at the same time very often. That is, we might examine two separate papers, and have one in each hand, but we look at one at a time. Having two documents or terminals open in separate windows/displays but both visible is a way for us to approximate this on a display. We have both visible at the same time so we can physically look back and forth between them easily. With a VR display, we might want a view like that, but when interacting with an item, it will likely be zoomed to fill 90% of the visible space, as that's how we generally interact with things in real life. When we don't, that's because of other limitations that prevent it, or because we need to split focus for a specialized task.
Personally, I would love to have a VR system that presented windows/screens of apps in a 3x3 grid (or more likely a 3x3 cross, a center item with items at the four cardinal directions), where the center item was zoomed to 90% of the display or so, but I could look around at the others, and could rotate vertically or horizontally to center (focus) a new item. This would be the "active" applications/views, and other things could be stashed to the side. It might start as a single item, expand to 2x1, items, then 3x1 (so I can look left or right), then 3x1 with one above, then one below, etc.
But really, per-monitor is too limiting. This really screams for a window manager that is aware of the display medium, and allows stashing of windows in a virtual desktop space. In a way, old Linux/BSD window managers like TWM and FVWM with their ability to have unconstrained (or very large) desktop spaces that you can move the viewport around is the paradigm we might want (with the addition of zoom).