G4's being moved to "Obsolete" status
Apple announced (via AppleInsider) that older G4 machines will be moved to obsolete status as of March 17, 2009.
Generally this means that Apple will no longer fully support the machine, software being developed is already moving away from the G4 and G5 platforms (iPhoto ’09 lacks some features on older machine via TUAW) and when a hardware repair is required a 3rd party generally will be needed (e.g. tekserve).
These machines have been discontinued from Apple manufacturing for about 7 years – so I think that is a “reasonable” course of action. That being said I still have a “mirror drive door” dual G4 which should be next on the chopping block 🙂