I just realized the glaring flaw in my plan to ground my outlets. Looks like that's not going to happen any time soon. I was thinking I could pull new wires up through the wall for each receptacle, forgetting that only one goes up to the box, and the rest are run around the room on the chain. So in order to do it correctly, I'd have to do a lot of drywall work as well. I don't think the increased value of the home would be worth the cost to redo drywall in each room, especially considering that I have plaster over drywall and it's not just a simple patch. I guess I'll do something else instead.