Yesterday, a vertical hairline of dark (dead?) pixels happened on my LG 42LB650V. This is annoying and, I suspect, likely to be permanent. I was kind of hoping a TV would last at least for two years before breaking down.
I would recommend calling LG. My LCD failed on my 55in a year ago, the television was out of warranty and I forced LG to send a technician to replace the screen. Now I'm a happy camper!