Flight MH370 — your theories?

[more details will be added here, I am just in hurry right bow]
What could possibly have happened with flight MH370? (Malaysian Airlines 9M-MRO 20140308, not to be consufed with 9M-MRD which was MH17).

I am glad, that the 25-hour-CVRs and undisable-able GPS have been introduced. Something that should have been considered years ago. But what do you consider as possibly happening?.