Actually, where melodies go, I know quite a few pianists and guitarists and even a few violinists/fiddlers who either have "memorized" a ton of songs or who just play really well by ear and can play the melodies beautifully even if they haven't rehearsed the songs recently.

As for singing lyrics and melodies perfectly (i.e., no wrong words or wrong notes), I can probably do that for well over 1000 songs at the drop of a hat (no, not 5000). It's the guitar work I need to rehearse, at least if it's not one of those standard 3 or 4 chord folk or c/w songs. (I play mostly rhythm guitar, though, not lead.)

I don't think the ability to remember melodies and song lyrics perfectly is all that rare -- especially for songs you learn before about the age of 16. Also, some songs' lyrics are easy to remember by virtue of the way the rhyme sequences fit both the story and the melody/rhythm. The more the songwriter uses words and melodic phrases that are clichŽd or rather arbitrary, and the less perfectly the lyrics are wedded to the musical elements of the song, the more it requires pure rote memorization to "remember" the song, and the more likely singers are to subject the lyrics to "the folk process."

Genie