I have just bought a 20" Cinema Display (love it). But I notice that my display has the same sort of leaks on black background that my old Dell 2005fpw had (bottom left and top right corners affected), although it is *far* less severe than anything from Dell. I would say it is borderline irritating, although I do tend to notice any sort of defect really easily.
This is an Apple display though, and I have spent a premium on their product for what I hoped would be good quality control. Is this normal?