I have an existing finished basement where I'm in the process of replacing an severely damaged plaster ceiling with drywall. I've got the entire thing open, and as it's an old house (1925) there is no insulation at all. Heat in this room is provided via one large radiator that is suspended from the ceiling (not my favorite feature, but it seems tough to move).
Is there much to be gained by insulating the ceiling while I've got it opened? I'm not too familiar with what is or isn't worthwhile - obviously insulation on exterior facing surfaces is good, but does it matter between floors?