It is surprising that there is no thread on Nana, maybe lost in the tragic-crash.
It is a great story. After seeing the attention live action movie has gotten, and with an experience of Hana Yori Dango on the genre, I have recently started reading it and I can say this is as powerful as HYD.
For the starters, this is the story of two girls of the same name (Nana) but totally different characters deciding to go to Tokyo at the same time, and starting to live together. Both, in some way, pursue the dream of being with/close to her boyfriends, one directly and the other through music. Since you may get distracted with the background introduction, bear with the first few chapters to prepare for the feast coming after the paths of both Nana cross. You will experience a great deal of emotional experience.