No computer is a "great investment"
it becomes an older model within months
I think that the poster meant to state that the "resale valuations" are high.
That being said, the value of the computer is what you DO with it
If you use a powermac to exclusively surf the net, it is not a good value, as you could use a mini
However, if you are doing video editing, it is a different story.
No doubt, however, that the intel announcement will lower PM resale values. But they probably would be lowered by dual cores, or any other hardware advance.
I think if you are using your computer for 3-5 years, you got your money's worth, even if you donate it