Having to play the music yourself really helps get it into your head in Ocarina, but the game has other memorable songs aswell, such as the Forest Temple or the all the songs from Gannon's Tower. A song that's always stuck with me is the Dark World song from Link to the Past.
Personally the MIDIs from TP never bothered me when I was playing but in a side-by-side comparions they do seem kinda bad.
Perhaps the wider variety of music in the game makes it harder to focus on a few songs making them more difficult to remember. I remember every song from the original Zelda, because there were four of them. That still doesn't excuse PH though.
"Now, a fun game should always be easy to understand - you should be able to take one look at it and know what you have to do straight away. It should be so well constructed that you can tell at a glance what your goal is and, even if you don’t succeed, you’ll blame yourself rather than the game. Moreover, the people standing around watching the game have also got to be able to enjoy it." - Shiggy
