I just bought a Macbook but want to get an external HD to keep all of my music and movies on, plus would like the ability to backup to it. I've noticed that I can buy a 120GB Western Digital for only $20 less than I can get a 320GB Iomega. Is there a difference between these 2 brands? Does anyone have any experience with either of these - is one better than the other? Also, let me know if there is anything I should look for when buying one of these to make it work best with my mac (ie. does it matter if it connects through USB or firewire?, etc). Thanks for your help!