I generally like my ghosts and keep them around. The ghosts of families I play, or favorite NPCs, anyway. If it's just a random townie ghost, I might get rid of them. That said, I do use the MCCC mod, and I use one of the features of that to turn off autonomous "Possess to Break" actions, so they don't go around breaking things in my game.
I also use MCCC to turn off the ghost-nights and alien-nights (and I think bear-nights too) at the bars, as while I enjoy having both ghosts and aliens around, I don't really want the game generating bunches of them randomly for those events.