Look at these stats:

  1. On Tuesday mine was the only PowerBook that I could see here
  2. On Wednesday I saw another
  3. Today I saw two more

That's exponential growth right there.  I also think with the people leaving Tech-Ed the number of Windows machnies has been declining.  If Tech-Ed were going on for two more weeks i'm pretty suer we'd see a complete dominance of Macs over PCs.