I think you're right Limnos. Itunes that will sync with an Iphone is beyond my reach whether I upgrade or not (and I can do that on the PC anyway), Youtube is working, Spotify is still working for the moment, I can do most things using either Firefox, Safari or Camino and I've managed to get the BBC Iplayer and ITV Player working after a fashion. It's the PPC processor that's the main sticking point rather than the OS and I can't do anything about that so I'm inclined to stick with Tiger as well.
That's a generous offer Knucklesmac and I appreciate it, but as I said to Limnos after seeing all the replies I'm not convinced there's much benefit to be had from upgrading. I might still think about it if there was a cast-iron way of restoring my Tiger configuration if things went wrong or I didn't like Leopard.