Ipod Nano or Ipods

I am still in the library. So do many other students. I have been observind other students for quite some time. Most of them have an mp3 player and majority of players are ipod family's. Is it a necessity or is it a trend? Actually I did plan to buy an Ipod Nano because there was a promotion, buying a Mac and an Ipod will entitle me to get a £100 rebate. But too bad the promotion ended and my bank account is not settled yet.