Silver: some of the navy surface vessels involved in this search, and sonobuoy-equipped p-3s also have capable sonar. Submarines are good at hiding, not necessarily searching a large area for flotsam or pingers (particularly not in shallow water) although of course it won't hurt to use them when they're already there.
it's hard to grasp that a large, modern airliner can seemingly disappear without a trace, and it's very disturbing...but on the other hand, we're speaking about tens of thousands of km2 search area, which will have been expanded several times now. I think it's safe to say by now ELTs wont help. I'd also dare to say that locating debris on the surface of the ocean, despite all modern long-range sensors, will ultimately still depend on mark 1 eyeball verification. In the absence of radio transmissions and acars data, until some physical evidence is found, maybe it's time to freeze this thread?