No amount of insulation is enough. But there is a solution. Fill your entire house with insulation. Just get a insulation blower, stick it in one of the rooms, and pump it until the whole house is filled. You will now have a well insulated house.
If anyone ever tells you you need more insulation, get a can of "Great Stuff" foam insulation, shove the nozzle up their ass, and release the contents of the entire can.