There’s no ending to the story yet so one of the best places to go for informed speculation on MH370 is PPRUNE, the Professional Pilots Rumor Network, where imagination is tempered with knowledge. For facts without speculation the site most likely to break actual news is the 7th Fleet Twitter account which lists out the activities of the Burke-class destroyer USS Pinckney, it’s two search helicopters and a supporting P3 from US airbases in Japan in 140 characters or less.
We have a few pilots among our readers, I’m sure they’ll have something to add in the comments.

If I were a betting man, I’d put my dollar on electrical fire/smoke in the cockpit.
Heh.