I bought a new 20 inch Core Duo iMac a few months ago, my first Apple product in four years. Its clean edges look fantastic on the desk and it sits like a big brother next to my old 12 inch PowerBook G4 .
But after a few weeks (conveniently just out of the 14 day return policy) I started noticing something weird happening after waking the iMac from sleep mode. At first there was a weird flickering across the screen, the kind of flicker you get when degaussing a conventional monitor. But this seemed to last longer and longer with each sleep and eventually took over an hour to clear itself, and even longer if it had been in sleep mode overnight.