I'll admit to be thoroughly impressed with my two Apple notebooks. I have both a MacBook (13in) and MacBook Pro (17in). I have no problem on either running pretty much anything I want, and on the 17in MBP I frequently run multiple virtual machines within Parallels. Part of that is undoubtedly due to the Intel Core Duo CPU. Of course, that doesn't mean I'm satisfied - I could always use more horsepower if it was available.

Intel's next revision, dubbed Santa Rosa, is due out soon, and I'd love to see it in some new notebooks, as it allows for some better performance increases, including the ability to ramp up the GHz on an individual core (instead of both at the same time), which should mean more speed with a lower power cost. This article goes into a bit more detail.