I experienced a rather annoying problem tonight. When coming back from sleep, my MacBook Pro “forgot” about its keyboard. No matter of power-cycling or removing batteries could fix it, and because it wasn’t “there” it didn’t want to reset PRAM either. External keyboard and mouse worked fine.
After much angry grrr’ing, I found that resetting the SMC worked.
Blogged in case other people have the same issue.
Update: it’s happened a few more times since then. Each time it disappears from the list of USB devices – external keyboard works fine. Lots of other people having the same issue, me and N have decided to downgrade to 10.4 this weekend and stick with that for a while.