A much drier, but also concise book is written by Alister McGrath and his wife Joanna. Alister is an Oxford scientist and theologian. Their book is called 'The Dawkins Delusion' and is well worth a read.
A friend of mine, Graham Veale, has written 'New Atheism - A Survival Guide'. Again this is a short book, and is a great introduction to the arguments put forward by the New Atheists.
I would heartily recommend watching the debate between Dawkins and John Lennox. Lennox is an Oxford mathematician. I find it interesting that it is Christians, rather than atheists, who circulate this debate. Lennox writes a really good book entitled 'Gunning for God - Why the New Atheists are missing the target.' This is quite a challenging read, but it is very interesting and hard-hitting.
Francis Collins is a world renowned scientist who was formerly head of the Human Genome Project. He writes 'The Language of God - A scientist presents evidence for belief.' I do not agree with Collins on every issue, and I found some of this book heavy going. However, it is a well-made argument by a top class scientist.
Finally, I always recommend Tim Keller's popular book 'The Reason for God.' It is a great book for anyone who seriously wants to think about Christianity with an open mind.