So I walked out of the Apple Store with a brand new 27" i5 iMac about 2 1/2 weeks ago. It worked wonderfully, no yellow screen, just some minor back-light bleed. I don't know if I'm starting to see things from being paranoid reading these threads, or if it's really happening, but I'm starting to see a minor yellowish tint on the bottom right-hand corner of the screen. Has everyone had the same problem of the yellow tint coming into play over time? or was it right out of the box??