I don't know if you can beat the original. This authoritative book, by Isabel Briggs Myers and Peter B. Myers, introduced MBTI to the masses in 1980. I would strongly recommend it to anyone interested in personality type. The book starts off by introducing MBTI and the preferences. It delves briefly into how MBTI is an extension of Jung's theory. After that, it provides some interesting statistics on type preferences in the general population and how it relates to the the frequency of certain characteristics. Ever wonder what the distribution of types is among national merit finalists, science students, or liberal arts students? You'll find out here. What I most like about Gifts Differing is that it lays out the system in a clear and concise way and then delves into practical applications of the system - such as the effect of the SN or TF preferences. There are chapters on learning styles, typical occupations, good type development and even motivation for type development in children. One unique aspect of the book is that it groups the profiles by dominant cognitive function. So for example ESTJs and ENTJs (both dominant extraverted thinking) are described in the same profile but with sections that explain the differences between the two types.
I give it 5 stars.