I read most of the books having an high score on this question - but not all of them (thanks God !) and I added the others one to my Amazon Wish List right away !
(Someone should create a list on Amazon for these books... Maybe a list named : "Stackoverflow best books ever" ? Anyone know how to do that ?)
To me, the best book ever has been Code Complete. It was a revelation. I bought the 2nd edition in english and then in French and I still think it should be a mandatory reading in any computer science school. Data structure is cool but Code complete, no joke, is much more important...
Then, my second best book was Writing Solid Code - having learn how to be understood, it was great to know how to write solid code.
Then a lot of very nice books but no one to mention here. Until 2001, I think : Framework Design Guidelines: Conventions, Idioms, and Patterns for Reusable .NET Libraries. A jewel ! I read this book many times and it's still on my desk, just beside my LCD, along with Code Complete (really !). I Love the way it has been written (love the comment that has been added here and there - books should all be written like that !)
But well, I forget the very first great books I've read ! The ones who make me love computer science, with passion :
- Compute! (C64 magazine - Will never forget Jim Butterfly :o)
- Borland C++ User Guides (the old ones, circa 1991, those who tried to introduce object oriented programming, very nicely written).
- Most Microsoft Developpement Tools User Guides, circa 1990-1995. Don't know who were writing them, but they was pretty cool ! I remember reading them late in the night, on saturdays...
Well, excellent question :o)