Adobe have announced that they are moving to 64bit only applications at some point this year. This means that Mac users will have to be running Snow Leopard...which means the final curtain for the G5. It also means PC users will have to be running 64bit systems too...the new applications will not install on 32bit systems.
It's always a pain when developers leave your hardware to linger with the other useless and outdated items in your studio...like the ashtray or the cheque book... but it's also a good sign. If Apple follow suit, we could have a fully 64bit version of Final Cut on it's way...and that would be worth upgrading for.
As for me...well, my G5 is struggling by with an additional fan i added to keep it cool and regular pep talks to keep it from dying out of jealousy of my better spec'ed MacBook. Looks like 2010 is the year i have to upgrade my main machine again.... going by the G5 experience, Apple will dump the Intel Processor the week after i buy my new Mac Pro.