It seems to me that we all know what should be done ... but that's a lot of money and many homeowners don't want to get that deep into it. All the talk of safety in the world will not get many homeowners to rewire the whole thing. What I do is approach each receptacle and circuit separately. Those that need a ground to function properly we try and ground, those that are normally used for stuff like 2 wire lamps, appliances (exclusive of the kitchen) etc we put new 2 wire receps in. Hopefully we come to a happy medium that all can live with (no pun intended).