Which screen model do you have?. Use the following to find out:
"Currently, MacBooks come with one of four LCD panels:
9C5E/5E9C - Chi Mei N133I1
9C5C/5C9C - Au Optronics B133EW01
9C5B/5B9C - Samsung LTN133W1
9C5F/5F9C - LG Philips LP133WX1
You can find out which panel you have by doing the following:
System Preferences -> Display -> Color
Open the default LCD profile.
Scroll down to number 13 and you should see model number listed there.
In my experience, I have been through three black MacBooks over the last week due to panel 9C5B, the Samsung. I have also read through other threads discussing issues with the Samsung panel. Both laptops I had with the Samsung panels were made in the 12th week of 2008.
All the laptop displays show some amount of dithering, as they are 6-bit panels. I think we all know this, but it bears repeating. The Samsung panels are horrible with their dithering. All grays show severe banding and dithering, including the OS shadows, pull down menu transparancies, etc. If you're also running Windows, you can see the problem a bit better. With Windows, you can just go to the display control panel and take a look at the gray background of the panel. It looks like a very warped checkerboard.
My final swap gave me a great LG/Philips panel, with a MacBook manufacturing date in the 9th week of 2008. The LG and AUO panels seem to be fine, with Chi Mei showing some washing out. The Samsung is disgraceful."