All my support for PPC owners!
I loved Tiger and I still have a pair of old eMacs, one of them running Tiger. I haven't used PPCs for a while as I have 2 C2D MBPs and an Air, but recently I got my eMac out from the garage and for parts, I bought another on Ebay. I thought that I would give one decent eMac for my brother's young daughters. He's an architect and he doesn't like the girls using his computers as there is a potential that they make him to tear his hair out by deleting files, dropping the laptops or changing some settings.
The eMac I bought on Ebay is running Leopard and there is a noticeable difference in speed, compared to Tiger. In theory, you can run Leopard on many PPCs, but what's the point? I can imagine that the only PPC confidently running Leopard is a G5 Mac Pro.
By the way, both eMacs work as they should, apart from one of them having the fan almost constantly running (which is still better than my 13" MBP) and the other has a slightly sensitive optical drive.
So for me, the issue is having Tiger supported. Young people, who never had an old Mac would not believe, how well these old Macs can do basic tasks. Frankly, if I could, I'd be running Tiger on my unibodies and on the Air (especially on the Air).
So the next time I will have a few hours, I'll do a clear install of Tiger on both and I'll keep one of them. It will be a great computer for watching DVDs in the pool house and running my music collection.
But it's sad that with some basic maintenance, these computers could satisfy the computing needs of millions, yet because of the lack of security updates, you can't really trust them on the internet where all sorts of passwords and account details are involved.