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[OngBonga]

A photon can have any wavelength, and therefore any energy.

Forgive me for arguing with someone far more qualified about these matters than I am, but really? I was under the impression that there was a lower bound, ie the Planck length, further that the Planck length represents the base unit of length at that wavelength would go up in these integer values.

You had me until "half of its mass."

That was pretty sloppy language, reading it back. Obviously a large black hole isn't losing half its mass in a single quantum process.

This really does come down to the idea that energy is quantized. I guess I need to read more about this concept but for the sake of argument, in the hope you can see what I'm getting at, let's assume it is, let's assume there is a smallest possible particle, with a corresponding antiparticle, and each has a mass of P. Let's say we have a black hole that has a mass of 2P. A quantum event on the event horizon causes the spontaneous forming of a particle-antiparticle pair. This pair is equal to the entire mass of the black hole. The particle escapes, and the antiparticle falls into the singularity. Now the black hole has a mass of 1. There is no longer enough mass to form a particle-antiparticle pair. This is what I meant by "half its mass". The final act of evaporation is for the black hole to lose half its mass, not all of it. The runaway evaporation process is the transition from a ridiculously tiny fraction of its mass evaporating, to 50%.

They can emit multiple photons at once, so long as all the conservation laws are followed.

Sure, but "multiple" photons will always be an integer value. Isn't this what Einstein means by "discreet" when he talks about packets of photons? You can't have half a photon.

Mass and energy are different things.

Not so sure. I might be wrong here, but I consider them to be related in the same way electricity and magnetism are. And while we might think they are different things, they're not, since it depends on your frame of reference. One person might observe an electric field while someone else observes a magnetic field.

I have a better idea of what mass is than energy though. Mass is a measure of inertia and is a property of things that move slower than light. That's your rest mass. But if you're moving relative to what you want to measure, it has some relativistic mass. That relativistic mass only exists though in the frame of reference of someone moving at a different velocity. If you're moving at 0.999c, then something else moving at 0.999c in the same direction has no relativistic mass and only rest mass, from your FoR. So relativistic mass is not a measure of inertia, it's a measure of velocity. I just turned relativistic mass into kinetic energy. And rest mass is essentially potential energy. Saying mass isn't energy seems the same as saying kinetic energy isn't potential energy, but again that depends entirely on your frame of reference.