The iMac has returned from the shop with a brand-spanking-new hard drive and 50 GB of memory. I am so happy to have it home. And thanks to some advice from my pal Zach Roesing, I was able to buy the hard drvie online at newegg.com for a reasonable $55 bucks. I did have to take it to a pro to have the drive put in; the iMac G5 version I have is not at all a user friendly when it comes to cracking it open and digging around inside. Still, the Help My Mac people did a great and very reasonably priced job, so the whole thing came in at under $200–less than the arm and leg I thought it might cost.
And I once again have access to my photo and design software, as well as easier access to mail. Oh my beloved iMac, I'm so glad you're back!