FWIW, I find I'm way more comfortable reading with a non-uniformly-colored page background on my phone or NookColor. The slightly mottled "paper" background that comes with CoolReader is perfect.
Somehow, any solid light colored background looks like dingy gray after I've used it for a while, and personally I find gray pages depressing.
With a bit of color variation on the page, that acclimation doesn't seem to happen.
P.S. I have to hold my Incredible about 3" from my nose before I can detect the pentile matrix effect.