After using the MacBook for several days now, I thought I would mention just a few misc. odds and ends.
It sounds like the left fan spins all the time. Even when running on battery. This is likely the fan that covers the CPU rather than the GPU, I'm guessing. I'm not getting the high-pitched noises that others have reported. I did have that noise issue with my old PowerBook G4, though. When running on battery, neither core seems to go above 20% usage.
I'm not seeing the band of white at the bottom of the LCD either. But as I mentioned in the last post, the backlight is definitely different on this machine than on their previous laptops. It's almost like there's some type of reflective panel back there, because as you move your head or tilt the screen, the brightness kind of rolls along with the tilt. So I think that brightness increase at the base has to do with the angle you look at the screen.
Last night I finally got a little time to sit down with the laptop plugged in and put the machine to task. I ran Google Earth under Rosetta while installing World of Warcraft. Both processes required Rosetta. The machine really began to heat up when that processor was put to use. It's definitely hotter than my old PowerBook G4 at peak performance. But even with the heat the machine ran smoothly. No hang-ups or pauses. One thing that really surprised me was the ability to run Google Earth under Rosetta with almost zero lag at all. Very impressive.
I would say my only real complaint with this machine compared to the old G4 is the width of the casing around the LCD screen. It's noticeably wider, mostly due to the iSight being built-in(and why 60 pixels were shaved off the LCD from previous PowerBooks.) But this is probably the only noticeable instance that the machine has regressed in design innovation.