Really? I have never read it, nor will I, but from what I hear it is a self-absorbed, silly, badly-written piece of shit. There are already too many history books worth reading and I bet that Mein Kampf is not one of them.
Well I wouldn't read it if you are looking for great ideas or a riveting plot, but it did have a major of influence on the nation of people who started the second world war and committed the most well known genocide ever, so for that reason it's worth reading if you are interested in history. Hitler was one of the most influential people of the twentieth century, so I would think it goes without saying that to understand the man it wouldn't hurt to read his manifesto/autobiography, especially if you are interested in the second world war. Obviously there are plenty of history books worth reading, there are enough worth reading that it's impossible for any one person to read them all in a lifetime. Maybe I should have been more specific and said anyone who has an interest in the second world war should read the book, and that a summary would probably suffice for most people, but I definitely believe if you have any interest in history you should at least learn a little bit about the book.