I've tried to put all valuables in the deep recesses of my briefcase to avoid any thievery. Of course, it wouldn't stop anyone from stealing the bag, but I live under the delusion that it might cause someone to be less tempted.
I have noticed security agents becoming more and more receptive to complaints about leaving my laptop behind while being given the full search. At JFK shortly after 9/11, they acted as if it was no big deal to leave a laptop just sitting out in the open without anybody watching it.
At SLC during the Olympics, however, when I said something to one of the agents, he stood guard over my bag and laptop until I had been wanded and had my shoes wiped down.