Specializing the question Who to address on the cover letter?, let's assume that you apply for a tenure-track position in the US in computer science, that the job announcement has no particular individual listed, and that Google/Bing/Yahoo led you to, say, "recruiting committee" (as opposed to "search team"). Then, which opening would be proper:
To Whom It May Concern
Dear Recruiting Committee
To the Recruiting Committee
Dear Representative of the Recruiting Committee
Dear Ladies and Gentlemen
How about the punctuation after the opening? No punctuation, a comma, or a colon? I.e.:
All are o.k. according to the broad English grammar, but, in academia things might be more special.