I just want a book on classical mechanics that covers the same ground as Goldstein's book but is more on the line of DJ Griffiths's Classical Electrodynamics. I mean less formal and more conversational.
John R. Taylor- Classical Mechanics.
It has very good and profound descriptions and derivations. Moreover everything is explanied simply with everyday language. As I can see it contains all fields of knowledge that is in Goldstein's book.
In addition it has tons of excercises of three levels of difficulty (marked with one, two or three stars). Some of these excercises are designed to practice computer programming (differential eqations, systems of them, some hard equations like in Fourier, making plots that illustrate solutions).
There's Introduction to Classical Mechanics With Problems and Solutions by David Morin. The UK Amazon readers so far love it, compared to the US where the reviews are rather mixed. Morin also brought up to date Purcell's classic Electricity and Magnetism, and the reviews for that have been universally outstanding: He added to the spirit of the book.
You won't ever get the perfect one mechanics book for what you want, but this book is original enough, authored by an instructor at Harvard, and with a conversational style that's probably what you're looking for.