I'll need to buy a new external hd to backup my new imac 2tb hardrive. 2 questions: I never liked the wd one i have for my old machine, can anybody recommend a good one for the new machine. And... I always shut my old wd external off after a timemachine back up because I could never figure out how to set timemachine to only do a backup every week or so. I think it wants to do a backup every hour and that seems silly to me. The less I use the backup drive, the longer it will last, right? So my question is: is my logic correct here or should I just leave the wd on all the time and now worry about it. What do you guys do? Hourly backups for a home machine just seem to "wastefull" to me. Thanks for your help.