consider using space above door and shelves instead of "built-ins" or bookcases, for max storage "wall of books" feel.
DIY Dining Room Open Shelving by The Wood Grain Cottage -- I would love these shelves for an office space or craft room.
DIY (Icelandic, English tutorial available) metal and wood shelves, using an Ikea HYLLIS shelf.
Book Storage Apartments or Small Spaces - love this bookshelf under the window seat! The window seat would make a great reading nook, too, especially with that lamp on the wall above .