you can always try her best album
-the greatest hits
and also her recent album
-ascension
-eighth world
her vocal is really great! and she can sing whistle note! if you notice that, she sing it in the opening of tsutsumi komu you ni. there's so much good songs from her, i'll recommend some of them
-into the light
-everything
-groovin'
-angel
-the glory day
-color of life
-tsutsumi komu you ni
and many many more, i cant think of any else but i will always edit my post
i just went to her concert last month, and it was really great! her vocal is amazing, i cant believe what i heard