If you are looking for inspiration I would recomend you to buy a bunch of these: http://www.aperture.org/books/book-c.../masters-books
I have a looked at a few of them and think itīs very good to watch other peoples work. Especially stuff that I havent even thougt of like the photographers that worked with surrealism. That is what I would have done if I had 50$ for more books.