Liza's Headband, why do you insist on restating every five posts that there is no perfect musical? The OP asked for opinions regarding perfect musicals, not a general consensus.
That may be your opinion, and a very valid one even shared by the OP, but there's no need to hammer it into our brains.
As for mine, I would say these:
A LITTLE NIGHT MUSIC
SHE LOVES ME
THE FANTASTICKS
MAN OF LA MANCHA
ANNIE
URINETOWN
LITTLE SHOP OF HORRORS
SOUTH PACIFIC
My own opinion, of course. They do exactly what they set out to do, and marvelously well. At least for me.
Keeping BroadwayWorld Illustrated