first love, 'cause it's the first j-pop song i ever heard and i immediately loved it and listened to it a million ba-gillion times and it never got old! i still listen to it every once and awhile and go "ah..." good memories...
;)
close seconds are probably final distance and eternally (but it's not on there...), i like the ballads. but all her stuff is good, lately i've been listening to colors a lot.