If any of you have an Aluminum 15" model and have recently noticed that your display seems to flicker in low light, then you are not alone. There is a bug in 10.3.8 which causes this screen flickering issue. The reason is that the 15" has light sensors inside the unit which can automatically adjust the contrast of your display, and 10.3.8 somehow conflicts with this feature. To fix, simply go into your system preferences / displays, and un check the box that says "Automatically adjust brightness as ambient light changes"
That's the temporary fix for right now. I hope this helps some of you out.