Olá!
Acompanhando ao longo dos anos - através de blogs ou palestras - as indicações de bons livros de feras como o Phillip, Luca, professores da caelum, etc. adquiri uma porção deles, tanto influenciado pelas indicações quanto como através de pesquisas na internet.
Quais livros acham interessante e importante ter sempre em mãos? Uma pequena lista minha:
Agile Java Development with Spring, Hibernate and Eclipse - Anil Hemrajani
Agile Software Development with Scrum - Ken Schwaber & Mike Beedle
Analysis Patterns - Martin Fowler
Better, Faster, Lighter Java - Bruce A. Tate & Justin Gehtland
Code Complete - Steve McConnell
Effective Java - Joshua Bloch
Extreme Programming Explained - Kent Beck with Cynthia Andres
Implementation Patterns - Kent Beck
Java Persistence with Hibernate - Christian Bauer & Gavin King
J2EE Development without EJB - Rod Johnson
Lean Software Development - Mary Poppendieck & Tom Poppendieck
Practival JRuby on Rails Web 2.0 Projects - Ola Bini
Programming Erlang (The Pragmatic Programmers) - Software for a Concurrent World - Joe Armstrong
Programming Ruby - Dave Thomas with Chad Fowler and Andy Hunt
Refactoring - Martin Fowler
Ship it! a Practical Guide to Succesful Software Projects - Jared Richardson & William Gwaltney Jr.
Test-Driven Development By Example - Kent Beck
The Pragmatic Programmer from journeyman to master - Andrew Hunt & David Thomas
UML Distilled Third Edition - A Brief Guide to The Standard Object Modeling Language - Martin Fowler
Head First Object Oriented Analysis & Design - Brett D. McLaughlin, Gary Pollice & David West
Head First JavaScript - Michael Morrison
Head First Servlets & JSP - Bryan Basham, Kathy Sierra & Bert Bates
Head First HTML with CSS & XHTML - Elisabeth Freeman & Eric Freeman
Head First Ajax - Rebecca M. Riordan
Eu gosto muito dessa série Head First - sei que alguns acham muito básico, mas consigo pegar bem 
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Abraços.