Here’s news to me: The word myriad should not be followed by the word of.
I know, right?!
I’m not alone in my surprise. The online dictionaries of Merriam-Webster, American Heritage, Cambridge Dictionary of American English and Macmillan all give examples of myriad being used as a noun, with myriad of clearly displayed as a viable option.
Dig a bit further, and you’ll find that myriad has been used as both a noun and an adjective for many moons — myriad moons, even. According to American Heritage, for example, myriad was first used as a noun — thus allowing for myriad of — and only in 19th-century poetry did myriad sprout adjective tendencies — myriad, sans of.
The latest rendition of the AP Stylebook, however, states that myriad is an adjective and — and I quote — “Note word is not followed by of. The myriad books in the library.” It makes no mention of myriad nor myriad of used as a noun.
Oof. After several decades of hearing myriad of, plain, ol’ myriad just doesn’t sound right to me.

"One is enough. If you are acquainted with the principle, what do you care for a myriad instances and applications?" — "Walden," Henry David Thoreau (photo: http://www.flickr.com/photos/kio/430028423/)
That being said, I asked my grammar guru, Bill Walsh of The Washington Post and The Slot fame, his opinion on the matter. He responded that while using myriad of isn’t technically wrong, why would I risk being considered wrong by those who follow AP style (which, my friends, is a whole bloody lot of folks)?
Why, indeed? And so there it is. AP says no of. Bill Walsh says no of. I, then, follow suit — no of.
Happy trails!
SAK