I have been using Eclipse as an IDE for a short amount of time (about 3 months of full use) and almost every day I learn about some shortcut or feature that I had absolutely no idea about. For instance, just today I learned that Ctrl+3 was the shortcut for a Quick Access window.
I was wondering what your most useful/favorite Eclipse features are. With the IDE being so big, it would be helpful to learn about the more commonly used parts of the program.