I have the 17'' Intel Core Duo with the built-in iSight. Earlier, I had a problem with the picture from the iSight fading to black within Photo Booth and iChat. I reset the SMC as suggested in one of Apple's tech support documents and it fixed the problem.
Later, I was going to trade this Mac to a friend, so I wiped the hard drive and reinstalled Tiger, but then the trade fell through. When I started up the Mac again, I discovered that the iSight was again fading to black. I reset the SMC again and the problem was solved again, but why did it come back in the first place?