I still have Tiger on my wife's PM G5, and this week its battery died (consequently Tiger didn't boot anymore). I've had the PM G5 since 2003, so it was about that time. I found a replacement at a local Radio Shack for $21 (what a ripoff, their own website lists it for $16), but I knew there would be a better deal elsewhere. Paid $7 (shipping included) from Amazon, and the G5 is working again.
That's a strange policy Apple adopted. Why can't they insert their own HD to do the testing without wiping customer's HDs? I'm trying to "ordain" my wife in the proper ways of better storage safety. She had been saving all her stuff on the desktop, so when the G5 apparently "died" last week, she had no access to any of her photos or files. It's been rectified now