Let's see -- one part "done badly" and two parts "done to death," mixed with "poorly (or worse) conceived" makes for an interesting list. This thread, which I just read in toto, having just decided to look over the discussion forum that Bill D keeps mentioning, keeps wobbling back and forth about the songs. We orta organize 'em:

Songs that are Okay, but Overdone (SOO Songs):

Michael's Boat (so overdone in its day that it's not done much at all, but still gets "those looks" when started); the Wedding Song (I, too, don't actually recognize this one, as in "hear it in my head when the title is mentioned"); Walting with Fauna ('nuff said); Waltzing Matilda (does the purported "charm" of this song derive from those Australian terms that the singer can claim to know when the audiene supposedly doesn't -- or actually didn't when the song was first commited?) (For the English majors out there -- you know who you are -- I bet you can't parse THAT sentence!) and probably most of the others already mentioned.

Poorly Done Ditties (Yes!) (PIDDY Songs):

MacArthur Park, and much of Paul Simon's later (post-1970) work (the charm of "Graceland" is NOT in the lyrical qualities of the pieces, and I say this despite very much liking to hear the CD); "Mao Tse Tung" by Ewan MacColl (if it's not his worst, I don't wanna hear what is!) A sh*tload of other topical and PC songs (Hugh Manatee is right up there, fer shur!) Most of those songer-singwriter songs that are so personal that ONLY the writer would sing 'em. I write songs, too, but at least try to come up with something someone else might LIKE to sing. (If anyone asks, I'll post "I Feel, I Feel" -- a collaboration with some friends -- but ONLY if someone asks.) (I can hear it now -- Don't Ask, Don't Tell!)

Well, It Sings Hard (WISH Songs) -- songs that are hard to do properly, but are done anyway, usually by people who shouldn't have attempted them: Star Spangled Banner ANY Leonard Cohen song and most old ballads with Phrygian, Lochrian or other "odd" modes in the tune. They get discovered and perpetrated on recording, then the vox populi attempt them, with disastrous results.

This has gotten longer than I intended, but my song-circle friends expect it of me, so I had to comply. Sort of the prose equivalent of "I keep getting asked for this song." If we look hard, we can find terrible songs, good songs done to death, and professional-driver-on-closed-course, don't-try-this-at-home songs. Our resulting list should probably be annotated to reflect the categories.