I would say get it definitely, but I am a PowerPC fanboy. Still here's some true thoughts: Your PowerBook will not fantasmagically explode the day Apple stops releasing new versions of OS X for it. Furthermore, when that point does come, you will at the very very least be running 10.5, which will mean your PowerBook will be even more functional then than it will be now when you get it. Then there's
this, and I've been on their forums and they say they'll soon be releasing 7448 G4 cores for the 1.67Ghz PowerBooks which have twice the L2 Cache, lower power consumtion and will likely be clocked at 1.84Ghz. And if you don't have a 1.67 then you can still get the 1.92Ghz or 2Ghz 7447 (same G4 as in current PowerBooks) upgrades. The situation is not as grim for PowerPC as the Intel collaborators would have you believe...