This message is for those of you a little unfamiliar with the English language: the word "magic" has 5 letters in it. There's no "k" at the end, "j" in the middle or any other letter that some feel compelled to throw into the word.
The argument that the "k" has been added to differentiate what we do with that of stage magicians is moronic. I've discussed magic in religion and history classes for years, and not once has anyone ever confused Celtic beliefs with David Copperfield. Besides, if we're to be so stubborn about the continued use of the term "witch", which some will swear only took on its evil connotations because of Christianity's perversion of the word, why so easily capitulate to the "theft" of the term "magic" by stage performers?
Modern use of "magick" appears to stem from Aleister Crowley, although many different reasons have been sited, including the mystical significance of the numbers 6 (the number of letters in "magick") and 11 (K is the 11th letter of the alphabet), that he wished to distance himself from the magic (no "k") practiced by the Order of the Golden Dawn, and, yes, that old argument about stage magicians. So, the use of the spelling "magick" might be acceptable for a follower of Thelema, but it makes absolutely no sense for a Wiccan, especially those ignorant of Crowley's reasons. And whatever his reasons, Crowley certainly never termed himself a "magickian", nor did he employ such other aberrations of the English language such as "majik", "majick", "magik", and "majic", not to mention the outright goofy displays of ignorance in words like "mystickal".
And don't tell me "magick" is the correct, historical spelling either. Yes, "magick" was once considered an acceptable spelling of the word, just as "olde" was an acceptable spelling of "old". That doesn't make you any less pretentious now.