Hello, I'm planning to buy a portable hard drive to use with my Macbook (yes, that old white MB with OS X 10.5.8 since 2007) and a PC (Win 7). I want to store and transfer movies, music, photos, documents... between me and my friends, and also, as a backup disk for my MacBook. But I've read a few posts with complaints that once you used HDD as a backup disk for a Mac, Windows PC can't read/write it? So, tech savies, please give me advices on which one I should buy? My budget is about 100$ and below, about 500GB storage. P.S: I'm kind of hitech-allergy, hi-tech items tend to mysteriously break down or malfunction when I use them, like 2 of my friends' Western Digital passport essential devices didn't like me, weren't recognized on both my MB and PC. Thanks in advance!