[vonmoltke]

I second all of the above. The Art of Electronics was my first non-required textbook purchase, and the 4th edition of Microelectronic Circuits was my textbook for two semesters of electronics and came in handy for multiple other classes.

To that list I would add the student manual that goes along with The Art of Electronics, as well as the Encyclopedia of Electronic Circuits series from McGraw-Hill. Both those choices are more on the practical side of circuit construction. The Encyclopedia in particular has an abundance of circuit designs with varying levels of explanation that make good starting points for learning about or experimenting with particular circuit functions.