It is actually a bit of a controversy.
After some in depth research I shall in the future recommend:
Dear Sir or Madam
....being the American I am.
Read this conversation/argument string:
Holy
(adj): Sacred, divine, blessed.
Holiday: a holy or festive day; a day off, vacation (also sacred)
Expressions: Holy Cow! Literally true in India.
Ex: Holly Mackerel! Delicious, healthy and full of mercury.