You can still get a burn-in-like effect with some LCDs, but it's not permanent as with CRTs. I once closed my laptop screen hoping for it to power down into standby. Didn't happen due to some glitchy software I recently installed that messed things up. I didn't know it didn't power off, so about 18 hours later I come back and see my screen has suffered burn-in. Freaked out, but eventually the display restored itself within a few hours. I heard some people having to wait days for the full screen restoration though.