And in my case, upgrading all my peripherals and VST units to go with it and upgrading to Cubase SX.
I don't even like using System 9. It's slower than system 8.6 and the damned 'sound thru' feature doesn't work. So if I want to monitor my mic or guitar while I'm playing, I have to constantly switch systems.
OS9 for using stuff like Halion etc... and then OS8.6 to record instruments.

My biggest drawback in not being able to upgrade to a lightning fast G4 is being stuck with a 266 processor. I can record up to about 128 tracks but they won't all run simultaneously unless I have an empty hard drive, run no effects, and space out the instruments so no more than about a dozen tracks are running at once. All the vst instruments have to be auditioned using an outboard sound module and then changed to VST instruments later.... Amplitube will only work on playback. And mixing a 128 track tune is impossible unless you mute half the tracks and do it in pieces.