Ok so I haven't been raving about black holes enough lately so lets get a nice good rave about turning Jupiter into one theoretically that is what this site is all about after all. Since in my nanowrimo novel I am using a society which has become an interstellar one by use of a Jovian singularity it wouldn't hurt to think about its implications a bit more.
One interesting thought is that the existence of a Jovian singularity implies that humanity became very certain at some point that it needed one. For some reason humanity can do certain very important things with a singularity that would be impossible without one. This means that before the black hole was created we knew pretty well what we could do with it. If we weren't really very certain then we would almost certainly not have been willing to sacrifice an entire planet just to satisfy curiosity.
Of course that also might say something about the government that would be willing to sacrifice a planet for whatever reason. The chances of a government being willing to get rid of Jupiter though are helped out by the fact that really ultimately Jupiter is valuable only as a research tool and as a gravity well that keeps its moons in orbit. As a research tool Jupiter is an interesting study of fluid mechanics and weather patterns and I'm sure of other things as well. As a black hole though it would provide an unbelievable basic physics laboratory. Plus as an added bonus the gravity well would be unchanged and so all the moons could still hang out in orbit. Of course probably collapse into a black hole of Jupiter would send the moons flying. I'm not sure how much energy would be released from the remains of the planet getting sucked in. If the collapse was quick enough it might just be a brief radiation burst and that's the end of it. But my bet is that it would take quite a while. If the moons of Jupiter house any sort of life (or come to by way of human habitation) then most likely we would not be willing to nuke them with the radiation even if the moons would still stay in orbit. But as far as a sci-fi like setting goes having a government that is willing to blow up Jupiter probably means either some sort of really crazy totalitarianism or plutocracy etc. I doubt a real democracy would ever get close to doing something so destructive but then... there are lots of ways people might be motivated to it. For instance if the earth has been thoroughly trashed and an 18 billion population earth is looking for a new place to trash.
Or maybe we want to go all doctor who and say that our future society is extremely power hungry and they think that a black hole would be a nifty way to get lots of energy at will. Actually this is probably the surest perk to having a local black hole. Since a Jovian singularity would be rather small actually it would put out quite a large amount of energy in the way of hawking radiation. But sucking away the rotational energy would probably be more efficient and if we wanted to we could even feed the black hole some gas and get the energy from the radiation which is probably the best way to go about things.