Of the books on that list, the ones I think you could call legitimately essential are: SICP -- K&R -- CLR -- Design Patterns -- Mythical Mammoth -- TAOCP -- Compilers (Dragon Book) -- Effective C++ -- Programming Pearls -- Peopleware -- Little Schemer -- Modern C++ Design -- The Practice of Programming.
 ... except I'd recommend Skiena instead of CLR.
 ... except I'd recommend Effective STL over any other Meyer book, and I also wouldn't concede that C++ is essential.
 ... except I'd recommend Lisp In Small Pieces, which I know is a totally different book, but do you need it and SICP?
 ... but only to someone new to programming.
 ... this book was wildly* ahead of its time and is no doubt overlooked because of it's patterns-y enterprise-y marketing.*
 ... 10 years ago I'd have recommended The Magic Garden but, even though I'd rather eat a bug than use a WinAPI system full time, it's hard for me to argue that Unix kernel design is as relevant now as the Windows kernel --- and, more importantly, there's no Unix book that does as good a job as Russinovich on the Intel architecture.