Aspen, try to listen at first her best albums - BEST OF SOUL with japanese songs and K-pop Selection, it's like coming through her first years in music industry. Later... I love BoA because in many albums of her almost all songs are great ^^ Listen VALENTI, LOVE & HONESTY, OUTGROW and MADE IN TWENTY (20) - japanese and My Name, Girls On Top/MOTO and NO.1 (imo the best of her albums in 'teenage' era) - korean.
EDIT: sorry, I haven't read that you've listen to BoS xDD
Maemi, I love your choice, you have a great taste <3
SONGS WHICH I WOULD RECOMMEND IN EVERY SITUATION

:
I know I'm crazy. But I have to do it xDD