The Theoretical Minimum by Leonard Susskind and George Hrabovsky
This is the physics book that's generating the most buzz just at the moment, by noted string theorist Leonard Susskind and George Hrabovsky, based on a general-audience course Susskind's been running for years. It's doing very well, with an Amazon rank in the 300's, which is kind of remarkable for a book with this many equations. Using calculus, even.
Source: scienceblogs.com