...Unless you know that you're buying into a dying architecture.
...Unless you know every single piece of software you will use throughout the time you have it.
...Unless you know that you can pay half the price for a quad G5 & build yourself a nice little gaming rig.
...Unless you want to have a machine that has real character & will put a smile on your face everytime you turn it on & hear those beastly fans roaring at you.
If the HD 4000 is not enough there will be no PowerPC card with powerful enough graphics.