I love Francis Scott Fitzgerald - The Great Gatsby and The Beautiful and Damned. Even if these books are not the best to read when it comes to improve speaking skills, Fitzgerald's poetical language is worth reading and enjoying his marvelous stories with rich thematic content embedded in social and historic pecularities. I admire his profound mind and the emotional depth.
Marc Haddon's 'A spot of bother' is a novel that gives you a funny look into the lives of ordinary people as well as it provides you with English in everyday life situations. It is advisible to look for books with lots of dialogue anyway. As our English lessons at school (a long time ago

) were focused on grammar and exams, I realised that my greatest problems were/are to speak fluently and react spontaneously.
'On Chesil Beach' by Ian McEwan is a wonderful novel if you like stories about the trials and tribulations of relationships placed on a historical cusp between the repressed 1950's and the liberated 60's.
Besides, I love reading biographies. I guess there are many interesting biographies you can choose from.
Other authors I definitely recommend are Oscar Wilde, Agatha Christie and some more, which I just can't think of at the moment.
As regards learning English by listening to music there is some music, which is both useful and good. Depending on what you like.

Music might be a problem concerning artistic license (using wrong grammar is not unsual, if you know the awful song "That
don't impress me much'

)
In Germany you can buy newspapers and magazines professionally edited and especially prepared for the needs of English learners. Perhaps you can find something like that in your country.
Another thing I prefer is to read postings by native speakers attentively and write down expressions and words which I find useful.