I always laugh at the argument about decorating with books. There are those that are appalled at the idea and those that embrace it and those that simply realize that if must put the thing down eventually it ought to look nice. I fall into the last category.
Personally, I am a fan of older books whether they be colorful or crusty.
There is something so romantic about old books stacked up. I do not, however, subscribe to the fashion of ripping off covers or white washing them for decorative purposes, But hey, you live your life, I'll live mine.
There is just something about the way that books fill in a space that magazines or other items just don't equal. I would not organize them by color but I have been guilty of that when I had to stage my house for sale.
I have become a believer in removing the paper covers but that is another war.