I've had my PowerBook for over 3 months now. Saturday, for the first time, it crashed. (Early on, I had a few instances where it would power down instead of going to sleep, but I found out what was causing that.) Saturday was the first time it crashed on me while I was using it. I've got to hand it to those Apple guys: crashing on a Mac has a much better user interface than the Blue Screen O' Death.
This morning, it happened again. Two crashes in four days. *sigh*. How disappointing.
Update: Again tonight. Time to figure out how to turn on crash dumps.