More evidence that 1.8 gamma is outdated and everyone should use 2.2 regardless of lines.
From the Apple's Snow Leopard page:
http://www.apple.com/macosx/refinements/enhancements-refinements.html
Gamma 2.2.
The default gamma has been changed from 1.8 to 2.2 to better serve the color needs of digital content producers and consumers.
I think the display looks better than ever with 2.2. It doesn't eliminate the lines but changes appearance slightly.