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I've done two things which together have dramatically improved the real and perceived contrast on my Kindle2.

1) Hacked/installed a much crisper font that does not use anti-aliasing. The built in font's anti-aliasing contributes to a lower real contrast ration because the letters contain pixels that are not full-on.

2) Skinned the body with a black stick-on skin. There are great, simple examples all over the web that demonstrate the fairly large effects on perceived contrast when a given field containing grey/black/white is surrounded by black as opposed to white.

Together, for me these have made the Kindle2 a pretty great reading device.

All that said, as for the iPad, I'm an unabashed lover, and intend to replace both my MBP and, once I test the book app (not to mention the kindle app...) my Kindle as well.

My hope is that when taken as a whole, including things like:
-throttling back the back light
-clever use of colored and 'textured paper' backgrounds
-great contrast
...the iPad will be a no-less great reader, and hopefully better than the Kindle2.
 
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