Here are my favorite solutions for books....
Hide them (if you are like me :)) with some fabulous drapes or why not Ikeas bookcases with mirror doors. That way, you hide the clutter, reduce dust and you open up the room with the mirrors. Love it!
You can also paint the bookcases in an accent color that complements the room. With this example, you get more lovely color and you get a feature wall in one!
In the above two pictures they have removed some shelves to create a box for art....love this! You can also paint that box in a different color to create a little bit of drama. Don't forget the lighting!
You can also use some cheap Billy bookcases from Ikea and buy moulding that you can add to the top and to some to create that X pattern on the doors. Very stylish and the "Billy" feel disappears.