That's interesting SPB. Brian Cox showed that the Crab Nebula had seven stars caught in small, frantic orbits around the entrance to the black hole. They weren't sucked in exactly, but couldn't escape. He described them as resembling 'bees around a honey pot'. So evidently, some of the matter doesn't move away and form new planets.

Also he said that huge eruptions of radiation can be observed shooting out of the hole at intervals.

I find the whole idea quite frightening, although I can't explain why.
I suppose one feels very small and insignificant in comparison to the Universe!