i am a new imac owner and have looked into external hard drives for time machine. the apple store and macmall recommend lacie vs. western digital. Tech at store recommends western digital and does not like that lacie lacks a fan and use other company's hard drives. Online, there are a lot of complaints about western digital studio book. help! i don't know what to buy. i read on macrumors that buffalo is good and cheaper but it is not cheaper online. do i need one that is geared to the mac so it is easier to install? seagate/buffalo require formatting for the mac-- i do not quiteknow what that means.