OK, I have a 13" MacBook Pro and a 500GB external hard drive that I used for a couple of months on my Dell laptop (now my brothers). I use OS X as my one and only computer but my brother and girlfriend own PC's and sometimes I transfer media from my Hard Drive over to their computers. What format should I use on my hard drive? I wouldn't mind if it was read/write only on Mac if that worked better on my Mac and I could transfer files to PC's from my Mac as opposed to my hard drive. Which format type would work best for my situation? Cheers guys!