Well, to be fair, one of the instances was my own fault.
1. Go to "My Computer"
2. "Ooo look, i wander what that USB video device is"
5. "Doh!, that'll be the iSight that Apple specifically says doesn't work then!!"
I kind of assumed when they said it doesn't work that it would not be recognised though, not that it would cause things to blue screen.
Other times were video driver related i _THINK_.
Yep, i'm guessing beta driver issues.
PS: The novelty has already worn off