CoreDuo MacBook:
- The screen flashes after wakeup
- Problematic networking
- Uneven backlighting & poor screen quality
- Occasionally it's been known to wake from sleep with the lid closed
Plus, so far I've had to have the power supply and battery replaced, and I've had to perform an 'erase and install' no less than 5 times to fix software problems (and there are still a few).
...Sure, it has its little annoyances but it's still a nice little machine. My iMac G5, on the other hand, has been absolutely perfect (knock on wood!).