Way back when, I wrote up a sort of an essay on the "I-V-vi-IV" chord structure, a.k.a. the 1564. While I have no stats to back this up, I'd blindly claim it to be the most overused chord structure in the past two decades. The 1564 was rehashed ad nauseum to yield a wealth of Top 40 hits--most of them lazy reconstructions of the same song.
Lest you think I'm off my rocker, someone went and made this handy Youtube clip, stitching together snippets from a bevy of tunes that make prominent use of the 1564. Behold:
You may recognize a few genuinely fine songs in that medley, and rightfully so. It should serve to underscore the fact that employing the 1564 isn't a strictly offensive act. In fact, on the Decemberists' fan-damn-tastic new album The King Is Dead, the penultimate track, "This Is Why We Fight", sports a flourishing 1564 chorus. It's a tad overfamiliar, but the song thrives regardless.
So anyway, hopefully that video proves that I'm not just spouting baseless gibberish...at least once, anyway.