The Norton Anthology renders the title of T.S. Eliot's poem as The Waste Land; a quick search reveals that this is not a choice of the editors, but the explicit intention of the author. (A simple, prosaic, and likely explanation of this preference, which has the unfortunate and disqualifying quality of failing to provide sufficient material for a blog post, is that the word "wasteland" arose in 1887 and did not come into common use until the 1930s, and Eliot merely wanted to preserve the original title, which he had come up with before he knew of the word.)
Rather than considering the ridiculous hypothesis just put forward, I will proceed to overanalyze Eliot's title. The separation of "Waste" and "Land" does not suggest emptiness as "wasteland" does; it rather indicates a land filled with waste--the refuse of the past inhabitants of the "Land", rendered useless by time and the ignorance of its current residents. The use of the definite article "The" ensures that we know that this is a specific, concrete time and place; he is not describing what a wasteland would be like, but the wasteland he actually knows.