The point is, Jobs made the claim that on a 'performance per watt' scale the PowerPC was giving 15 units, and Intel 70.
Now that IBM have come out with low power PPC chips that use less power than Intel, even presuming the Pentium M is an equal to the G5 (it isn't) at the same clock speed, the 15/70 quote looks a bit odd.
As for opteron v G5, I partly agree. There's swings and roundabouts on either if you want to claim top performance dog. There's nothing on the Intel side bar Xeons that come close and the Dual core Pentium is a joke. Dual core Opterons though are extremely expensive and although you may be able to buy a system with them in, you're not going to get one for less than a PowerMac without some compromise. $4000 is more likely. Will they be faster than the Dual-core G5? - time will tell, the Opterons clock in at only 2.2Ghz.
So, IMHO, the G5 is still holding it's head up above water in every way except for laptop speed - 1.6Ghz isn't enough for a low power chip. And laptop speed is much more important to Apple than server class speed
But this isn't about what is shipping now, it's about what is shipping in 18 months-2 years time. And then AMD are predicted to run out of steam having canned the their successor architecture twice and Intel seem to have finally found their groove again with Pentium M.
