Thanking the Little People

In a recent team crossword-puzzle-solving effort, there was some controversy as to the correct spelling of the plural form of 'dwarf.' I assumed it should be spelled D-W-A-R-V-E-S, but both my assistant (assistee?) and the puzzle itself required that it be spelled D-W-A-R-F-S, so I assented.

Obviously, though, I looked it up on wikipedia later, and found that both were correct. Here is a direct quote:
"Many grammarians prefer dwarfs, many fantasists prefer dwarves."
[Imagine that taken out of context...] Basically, when referring to humans affected by dwarfism, it's 'dwarfs'; for mythical creatures: 'dwarves.'

Now you know.