This is a petition started to bring them back for all states.
I think not only would it help the families stay together, it would help with divorce rates, issue children have about being separated from parents (I know my two year old would love to spend the night with daddy).
It would also help cut down on prisoner violence, the guys would have much more to lose. There would be less tension, it may even cut down on rapes, and disease transmission, since the guys would be less likely to engage in unsafe behaviors.
Heres a couple of sites on conjugal visits as well