- Practical Common Lisp
- Data Structures and Algorithms with Object-Oriented Design Patterns in C#
- Squeak by Example
- The Art of Unix Programming
- Practical PHP Programming (Wikibook)
- Foundations of Programming
It just occurred to me how eclectic this list is. It's not every day that you see books on Lisp, C#, and PHP collected in the same list. The Internet is as wide as it is wonderful. :)
Additional Note: As some alert readers over on reddit noticed, the online version of Programming Pearls is incomplete, so I've decided to replace it on my list. Sorry I didn't catch this sooner, but you can still enjoy the 3 sample chapters that the author has graciously made available for free.
And here, for those of you who don't read blog comments, are a few bonus picks submitted by readers of my previous post.