I'm sure this thread has been done dozens of times before, but I did a little digging and it didn't look like it's been done recently, so I figured I'd make a new one instead of trying to find and revive an old one.
Anyway, my favorite is:
K.K. Lament
I swear I've heard a similar song sung by an actual person, but I can't remember the name of the vocalist or the name of the song... All I remember is it was sung in Japanese (it'd probably be easier to find it if I could understand Japanese and knew the lyrics lol), and the person singing it was a man with a rather deep voice. (it seemed to be an older song, too)
I don't have all of the K.K. songs yet, though, so it's possible I'll eventually find one I like even more than that one.
I legit have been playing the live K.K. Jongara version on repeat. And then Lucky K.K. (live) has been one of those melodies that somehow stuck with me for so many years since I first heard it on Gamecube, and whenever I hear it again in the newest AC I get a sudden nostalgia blast.
Oh wow. I'm glad I made this thread.. it reminded me that today is Saturday and I haven't gotten my CD from K.K. yet. LOL *requested him to sing K.K. Ballad*
KK Steppe and KK Condor- As a fan of birds, I was amused by their names and how they both shared avian names. Both songs are immensely catchy, too. I had KK Condor playing in Maxwell's house until Fireninja kindly gave me KK Aria.
KK Aria- This is more nostalgic bias than anything, but not only do I like this track's slow, stately tune, but it also influenced the name of one of my OCs.
Steep Hill- It's pretty intense and formidable. I wouldn't be surprised to hear something akin to that in a Legend of Zelda dungeon.
Neapolitan- Like I initially witnessed in Erik's house, Neapolitan is the icing on the cake when it comes to creating a homely feel. I have it in my own Cabin House, and it ties together the room superbly.