Michael, sorry to hear about the loss. Most robberies are from people that have been in your house before. I would have the police consider the ex. who steals a futon mattress?
Bill has some really sensible advice that all should consider. I've done what Bill has suggested on #3 with e a big screen TV mounted to a wall that has a lock, cable lock, and bent electrical staples that will take me about an hour to undo to remove it if I ever need to. I've had friends say that any thief would just break it out of frustration, but given the alternative of a thief taking it, or destroying it, I'll go with the latter.
But I would add #5) During extended absences, put easily carried items (jewelry, tools) in places people wouldn't think to look (bottom of hamper for jewels, power tools in an old xmas tree box with dusty stuff on top of it).
With regard to motion sensors, put them up in hard to reach areas, and put them where they catch action side to side. They are essentially heat differential sensors that look for side to side action. In many cases you can walk right towards one slowly and not set it off. And do NOT put them near heat/air registers.
All my advice comes from the experience of being robbed before.