... A C2D desktop at $1500 would compare very favorably to the $2500 Xeon machines, on a dollar for dollar basis.
The "desktop" C2D, socket T, cpus are certainly a better bang per buck right now, offering up to quad-core performance, at somewhat lower prices per Ghz than the socket M "mobile" cpus Apple makes use of in its minis, iMacs, and notebooks. But Apple's only been making use of Intel cpus for a little over a year now. Thus, Apple's has an extremely small "track record" for us to draw on in regards to how they'd made use of Intel's products.
If Apple announced a new system based on Socket T "desktop" cpus I really wouldn't view it as a "radical" new shift in Apple's Intel computer line, since that line is really just in its beginning stage when you consider the bigger scheme of things... yet there's always "experts" that claim such a thing would never happen. I think such folks are living in a pre-Intel world, however.
I think there's hope that Apple may expand its Mac line... especially when you consider the fact that Apple is really just beginning to figure out its potential market for the entire Mac line. But whether or not Apple might (or might not) do that is anyone's guess...
Personally, I wish they would. I don't want a "all in one" system designed to look like something from a Zen Garden. Function is much more important to me than form. And since computers are how I make a living, and I own the business I'm not going to pay (waste) >$3000 for a "pro" computer that will be outdated in a year or two. The biggest bang per buck in computers is always in the mid-range, not in the high or low. In other words, why pay 4 times the price for only 2 times the processing power, if you don't *need* that power?
Right now, I can do >95% of my work on my old G4 DA @ 1.6Ghz. And that means I won't be in the market for a new Mac unless my old G4 dies or Apple decides to make a suitable (non-all-in-one) replacement for it. I can get by until then by making use of more powerful machines I own running Linux and Windows in the few cases where the G4 won't handle what I need to do.