A song of ice and fire: Enhanced Editions
I'm a massive fan of the genre that Ice and Fire falls into and I've always enjoyed those little maps you get at the beginning of books that introduce you to the fantasy world you are about to enter- it always makes it seem a little bit more real.
The enhance Song of Ice and Fire is one of a series of enhanced editions from Harper Collins and this version is from iBook. While the character glossary and audio snippets are interesting its the embedded maps showing where each charater is at the start of the chapter that fascinates me. Simple idea but really useful in a type of book that could be sprawled over a whole world with alien sounding place and person names.
It's just a pity I don't have an ipad to read it on as I really want to see how good it is myself.