I will recommend books that I have and books that I heard of:

Books that sparked my interest in all of Mathematics (BTW, I'll be glad if you recommend any Abstract Algebra books):

- Calculus, Howard Anton.

- Calculus, Spivak

- Advanced Engineering Mathematics, Erwin Kreyszig

- Elementary Number Theory, David Burton.

Computer Science/Engineering:

- Data Structures and Algorithms, Adam Drozdek

- Digital Design, Morris Mano

- David Patterson and John Hennesey's books

- Mastering Embedded Linux Programming, Chris Simmonds.