My all-time top business read was
Get Client's Now! by C.J. Hayden. I read it got part way through the program and had to stop because I was getting too many calls from potential clients. In fact, I need to do it again but keep having things come up that makes me not want to focus on it. Plus, this time I really want to do it with a buddy to have the added accountability.
One book I absolutely loved (and have had to replace because I shared the first copy too many times and couldn't remember the last person I gave it to) was
Entrepreneurial Freedom by Jeannine Clontz and Lauren Hidden. It's kind of basic about starting your business, but I've used it with a ton of people that I've helped get their businesses started.
Another book that I read and absolutely loved (though I didn't keep because I new I wouldn't go back to) was
Nice Girls Do Get The Sale: Relationship Building That Gets Results by Elinor Stutz. I heard her speak at a conference and ended up spending a lot of time talking with her afterwards. I read her book cover to cover very quickly and picked up a lot of tips. It's written more toward women in sales of a product but still very good.
The first two are still on my bookshelf and will remain there.

One other book that has been highly recommended to me is
Getting Things Done by David Allen. I just struggled through the first chapter and have had a hard time picking it up again. I know I need to but something better always shows up.
That's just from my regular bookshelf. I have some ebooks that I love too but, personally, I prefer regular books. Most of the time I download an ebook to read later and never get back to it.

Although, I do have some ebooks I could recommend.
I love to read. I've seriously been thinking about renting a cabin on one of the nearby lakes and bringing just business books and my laptop with NO internet so I could write, read, process things, and implement some of what I learn.