I love any book that has a picture that makes you want to build a model of it.
I often buy books just for one picture inside its cover!
Ten years ago I bought Gunboats on the Great River which after eight years has led to the construction of the 1/32 scale HMS Gnat. As I said in my build thread research is one of my favourite parts of modelling. The best picture books for ships I have in my collection are the Royal Navy in Focus, these have started several projects which may appear on the warship build threads in the near future.