"GLAMOROUS SKY," sung by Mika Nakashima, who performed the role of Nana Osaki in the movie, is famous as the song inspired by NANA. But I prefer the one used in the anime series: "rose," sung by Anna Tsuchiya, who I guess is far similar to the character.
When I went to Ebisu and stayed all night with my friend about a month ago, we went to Karaoke. After singing a couple of songs each, my friend sang a Rock song, and then I felt like "I wanna sing rock too!," so I picked up "rose" to sing. Since it had been a few years since I listened to it last, I missed some melody, but the song was still so cool; Turned out, I often listen to this song these days.
I need your love. I'm a broken rose. Oh baby, help me from frozen pain with your smile, your eyes, and sing me, just for me