The one that they had on the show was Pride & Prejudice by Jane Austen -
As one of my favourite novels of all time, this excited me more than a little bit. Not all of the images are amazing but I really love this one. Unfortunately, given the length of novel, it's a A0 sized poster, which could prove tricky to get a frame for, but it is pretty special. At £56, it's kinda pricey, but if I had that money spare I wouldn't even hesitate to buy it.
Other ones that caught my eye were Romeo & Juliet (£40)
and Peter Pan (£45)
which makes my heart swoon a little at the thought of having it in a little boy's nursery...
I just think they're amazing, really personal and interesting, and way affordable when compared to 'proper' art. I think one or all of these are going on my real life wishlist (maybe even my Christmas list). As a full on book geek, they essentially fill my heart with joy. Don't you think they're delightful? I'm swooning.
P.S. I wasn't paid to write this or anything (I wish), I just genuinely am in love with this idea.
Edit: Whoops. Totally forgot to say where you could buy them/where I got the pictures from! Too excited clearly. All theses gems can be found at http://www.spinelessclassics.com