...you want to 1-up him you'll have to go for the quantum mechanic explanation of bonds. As far as *useful* models for chemical bonds go, even chemists use something pretty far from the "truth" . There are valence bond theory, orbital hybridization, resonance, and quite a few more.
When it comes to explaining nature, you use the model that is most USEFUL for what you want to explain, not for the most complicated one possible to impress your peers because you are so smart. :) That is why in many books atoms are still represented by red, white, blue "balls" and no one complains about it.
And by the way, the in the oxygen-hydrogen bond oxygen actually does sort of "borrow" the electron - the probability distribution for the location of that electron shifts towards the nucleus of the oxygen. That is why water molecules, while actually neutral (if not ionized), still act polar - the oxygen is essentially negative, the hydrogens positive. There is no equal "sharing".