computer_science

Programming: SICP (aka the Wizard Book) and accompanying lectures, How To Design Programs (you're going to want DrRacket for these)
Architecture: The Elements of Computing Systems (aka Nand2Tetris) and accompanying course
Algorithms and Data Structures: lectures for the Algorithm Design Manual
Mathematics: Discrete Mathematics (PostScript file!), Essence of Linear Algebra video series
Operating Systems: Operating Systems: Three Easy Pieces
Networking: Wireshark Labs from Computer Networking: A Top-Down Approach
Databases: Readings in Database Systems (aka the Red Book), UC Berkeley CS 186
Languages and Compilers: Stanford Compilers course, Make a Lisp
Distributed Systems: Distributed Systems

also…

Dictionary of Algorithms, Data Structures, and Problems of http://www.nist.gov/dads/
Structure and Interpretation of Computer Programs http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-4.html#%_toc_start
Parsing Techniques - A Practical Guide http://www.cs.vu.nl/~dick/PTAPG.html
Common Lisp the Language http://www-2.cs.cmu.edu/Groups/AI/html/cltl/cltl2.html
“On Lisp” by Paul Graham http://www.paulgraham.com/onlisp.html
An Introduction to Programming with Threads http://citeseer.nj.nec.com/birrel89introduction.html
a basic introduction to monads, monadic programming and IO http://www.dcs.gla.ac.uk/~nww/Monad.html