I'll cast another vote for each of Programming Pearls and The Mythical Man Month.
I'd also like to nominate Kernighan & Plauger, Elements of Programming Style, Kernighan, Software Tools, and Yourdon, Techniques of Prgram Structure and Design. One could argue that all of these last three are outdated, as they predate oop. One mustn't forget Knuth Art and Science of Computer Programming, although I suspect he will never finish it; I don't think volume 4 has made it onto store shelves, let alone 5 through 7.
Slightly further afield, I recommend Petroski, To Engineer is Human, Karen Gordon's lovely books on grammar and punctuation, and Neville Shute, Slide Rule, which is not a history of an analogue computing device. I also support those monks nominating Strunk & White's Elements of Style.