Can anyone tell me which brand of external hard drives would be the best to use for my iMacs? Someone picked up an iomega for me, but if I had been there, I never would have bought it. I have had nothing but trouble from iomega, and I am going to take that one back. What is the best brand? What should I look for? I have files that are larger than 4GB. Which harddrive will allow me to transfer those? Thank you.