How a Bible Can be Useful to Someone Who Isn't Religious
Morality
   Recently many 'atheist churches' have started popping up around the world which are aimed at providing a sense of community and a chance to reflect on morality - something that is a big part of religion and that many people miss. The Bible teaches us many lessons on morality and has some very insightful ideas regarding how to treat others and to live an essentially 'good' life. If nothing else it serves as a reminder to consciously try to be a better person - something which many people seem to overlook.
Self Development
   This isn't the only thing that the Bible can help with either though, and many of the lessons and messages therein can help us to live better lives in other ways too. For instance the whole idea of lent - of arbitrarily sacrificing something from our lives for six weeks - can help us to build better self-control and discipline.
History and Literature
   Furthermore though, the Bible is in itself a very important book from a historical and cultural point of view, and it still plays a big part in our modern lives. If you talk with a group of friends for instance who are religious, being familiar with the Bible will enable you to better join the discussion and to empathise with their viewpoints. Reading the Bible can meanwhile help you to brush up on your general history and deals with many subjects such as Rome and ancient Egypt. Finally, many literary devices in great works of fiction will be based around parts of the Bible or at least reference it - you'll even learn the origins of many common phrases and quotes just as you would by reading Shakespeare.
Stories
   The Bible is also filled with all kinds of great stories that cater to a wide audience. If you're looking for something to read your children at night, then many of the stories work as great fables or parables which can help to instil messages. Meanwhile though if you're looking for something a bit different, try reading revelations and looking at what all the symbolism means. This is the story of the apocalypse and it is at once action packed and completely cryptic.