JAD and Jadclipse allow you to decompile classes directly in Eclipse automatically, great for debugging 3rd party code or just research in general
http://greatwebguy.com/programming/eclipse/decompile-java-classes-automatically-in-eclipse-with-jadclipse-and-jad/
Just a shortcut for Eclipse that I appreciate and use religiously, if you don't know about it Ctrl+Shift+R could change the way you code.
http://greatwebguy.com/programming/eclipse/eclipse-open-resource-shortcut-ctrlshiftr/
Running a server in the IDE can sometimes be flaky, the default settings and server.xml don't always work they way they should, this should help you get over those problems with Tomcat and Eclipse.
http://greatwebguy.com/programming/eclipse/make-eclipse-and-tomcat-play-nice-together/
