As far as Oculus goes, this probably takes a whole heap of pressure off of them. Now they can act like one of the units of Bell, and just work on the thing, rather than worrying about pleasing investors or turning a profit anytime soon. Assuming FB doesn't do anything crazy, this will only help them and the tech.
Edit: the thing that should be worrying both companies is the potential developer backlash. Not everyone loves FB, as the comments here attest. Perhaps an investment rather than an acquisition would have stirred up less vitriol.
I suspect this in Facebook-OVR. FB might ruin it, a la Yahoo-Flickr, or leave them alone, but Facebook isn't really making headlines these days, and OVR is, so now every OVR story will now have to mention Facebook. It may not turn out this way, but there's no reason why the pairing has to be tightly coupled.
Tightly-coupled Facebook-OVR would shock me, definitely.