Congrats on your new (to you) G5 iMac; I gave mine to my sister and bought a refurbed 24" Intel iMac earlier this year. But I must say, I thought the chin on the white G5 was more pronounced than the one on the aluminum version (which instead has the 'raccoon eye' screen treatment.) It didn't specifically bother me, but I would just as soon see them all disappear.
At the current trend of miniaturization (has an iPhone surpassed a Cray-1 in compute power yet?) there's no reason to expose anything to the user except the display itself and I/O ports, if the 'internals' shrink to zero. And I think that's the direction that Jobs & Ive have been heading since 2000.