Classic computer science text and papers on the web
- Structure and Interpretation of Computer Programs is arguably the best single text book
- Original 'Lambda Papers' by Guy Steele and Gerald Sussman
- General reading on Kolmogorov Complexity; for example: 1 2
I find it interesting to re-read material that I used many years ago - you get a different take on papers and texts after years of experience, making them interesting in new ways.