I just updated my laptop to OS X 10.7, so several of the PPC-based applications I use (Sound Studio, m2s, Photoshop CS) don't run any more. Fortunately, I'm also in the process of making the computer dual-boot between Lion and a small Snow Leopard partition, so that I can combine the powerful features of one system with the compatibility of the other. Someone even pointed out that a copy of Parallels is capable of running either Windows or Mac in an emulation mode, so I might try that so I can run both systems at the same time.
Anyway, there'll be a short downtime while I get things back together.
Yeah, I remember I had Classic on my g5 imac, and then to my disappointment it stopped working in an update. Fortunately I still have my 700mhz iMac g4 which runs classic great.