Psssh. Apple would be making a massive mistake if they killed off the Mac Pro. Sales are DOWN on it only because it has not been updated in so long.
But let me play devil's advocate for a moment. In desperate need of a Mac Pro, I *almost* built my own. But have decided to wait to see what Apple decides to do.
Sure, it's not legit, but you could *cough*, hypothetically build a Hack-Pro for around $1500 that has MORE power than the $5K Mac Pro.
I would definitely prefer a Mac Pro. Took me a few years to switch to Mac's from Window's computers. But I love how easy the Mac Pro's are to swap parts on. Install new drives, etc.
When they mention the fact that they could upgrade the power of an iMac for the power hungry users... yah, that won't happen.
My 3-year-old 24" Intel Core 2 Duo 3.06ghz iMac, with a Geforce 8800 GS video card, runs so hot, that they have had to replace the LCD panel (due to image persistence) 2-3 times, and the video card due to overheating, twice. An iMac isn't, and never will be an industry-grade system for doing video editing or graphics on.
Not to mention, the cost of a high-end iMac (27", 2tb hd, 2gb video, 8gb ram) is almost $3,000. Add to that, the cost of adding any external thunderbolt cases, add-ons, and you'd be better OFF, buying a Mac Pro.
Either Apple comes out with a new Mac Pro, or I build one.
I wish I'd never sold my quad Xeon to buy this iMac >_<