So essentially, dcantrel, you're saying, "OK, calm down -- it's really just that Apple has designed an OS to make 80-90% of their user base's machines obsolete."
Really, though, perhaps we can take a quick look at GNOME running on Linux PPC, examine the app launch times, screen redraw times, and other general visible indicators of speed, and wonder anew why this is such a problem for OS X -- and, in a more depressing vein, why the OS X project started with the mach kernel....
And claims of 10.1's improved speed are moot, of course, in situations where an upgrade to 10.1 from 10.0.4 has VISIBLY SLOWED a machine.