Luckily the iMac intends to attract a quite different audience than the Peg does. It's neat, sure, but the Peg is more compareable to the G4 towers.
And remeber the G5 is also only "boiling with water", I guess a G4 1.5 ghz will not be that far behind those G5s.

But sure, the design is neat (well, but I wouldn't buy one, but if I would buy a 5th computer (no, I won't currently) then either a G4 laptop to have it slim and mobile or a dual G5 for speed, but not this mixture of both...) and the price is surprisingly affordable for an iMac.