We seem to have enough children's books to start a small library- they're the one thing I refuse to part with!
My kids share a (small) room and have loads of bookshelves!
A GLTC 'dolls house' bookcase
2 x GLTC star shelf bookcases that fix to the wall and have hooks underneath for hanging coats etc. these are most suitable for 'chapter' books i.e not large books.
2 x tidy books bookcases which are very slim and don't take up much room- the books face outwards and you can fit quite a lot in although obviously you can't see the ones that are behind
They then have a GLTC abbeville 4 cube storage unit- 2 'cubes' have canvas boxes in for toys, the other two have books in and it looks lovely.