Thank you for this post. I have read and listened to Purple Cow, and my big takeaway is that in business you must be unique, and there is always room for innovation.
I would have to recommend anything written by Zig Ziglar especially "Secrets of Closing the Sale" which Changed my world.
I am currently reading DotCom Secrets by Russell Brunson yes I did spend the $10 for the hardcover edition. So far I am very impressed and am taking a bunch of notes, and am excited to try some of the secrets.