Janie, I have an iMac very similar, if not identical, to yours. I did offload itunes and some photo archives to an external disc a long time ago (VERY simple - plug the disc drive into the USB port and electricity, and it'll appear as an icon on your desktop. Drag and drop the files you want to move. You can open the drive icon and it'll look like any other file. You may have to set preferences in itunes to find the libraries. I can't remember) So far, I'm using 50 of 400 GB on my main drive. I upgraded to Snow Leopard awhile ago, too, with no demand for more memory. I've allowed the auto-upgrades to OS, itunes, and Safarai. Occasionally, I've had problems with Flash, too, but I've managed to ignore them. I looked at Lion, and have no need for handswipes, apps, or any of those controls, but that's probably the future staring me down. This setup workes better and has outlasted my kids' windows machines by years. I'm not looking for a replacement yet.