I am a PC user who is looking to switch to a 20" iMac. I would like to get a nice big hard drive in it, but I wonder if 500GBs is to big? Really what I am asking is what is the upkeep like on a 500GB hard disk. I ask because a 500 in a PC could be a nightmare if you don't have a super fast processor. I usually have to defrag my current disk (on the PC) at least once a month to avoid serious problems. Seems to me that when I used to work with Macs many years ago, you had to defrag them from time to time. I am just trying to get an idea if 500GB is going to be a pain or not. I can use the space. I plan to try and put all my CD's into iTunes, I download and save a few video podcasts and I plan on doing some home movie projects. Thank you for any advice you may be able to offer.