Eclipse was my main IDE for all my JavaEE and Web development all the time in my career. For all plain Java development and Android app development, I used to revert to IntelliJ IDEA Community Edition, which allows only plain Java development and not Enterprise Java development i.e. JavaEE or Web Development [Spring, Hibernate, Grails, etc]. For more info on what is allowed and what is not allowed in Community Edition, please refer this matrix on JetBrains website. Post the Mayan Doomsday Offer by JetBrains, thanks to the 75% steep discount on 20th December, I now have IntelliJ IDEA Ultimate Edition as well.
Eclipse is open source and is free to use. It is a thriving community for individuals and organizations which collaborate on commercially-friendly open source software. So, over a period of time Eclipse grew on all developers and almost everyone uses it as their main driver for development. And what's more with Scala, Groovy and Android teams giving support for Eclipse as the first IDE has given it a good momentum in the past few years. The plugin ecosystem is huge in Eclipse and in fact, these plugins have helped Eclipse grow as a platform what it is today. Such is the popularity of plugins in Eclipse ecosystem that they have also launched Marketplace for Eclipse plugins. If something is missing in Eclipse, don't worry, just check the Marketplace for the plugin or else you can develop a plugin in no time actually. That has been the mindset of a lot of Java developers in Eclipse ecosystem. There are thousands of plugins available for Eclipse right from customizing the IDE to Maven integration to Python IDE to Spring IDE, for Checkstyle, PMD, FindBugs, etc.
With all my prior experience in using Eclipse, I have some goto plugins which I install the moment I get a brand new Eclipse version. Here is the list of all Eclipse plugins which I have used till now with a short description and the Eclipse Update Sites of the plugin.
Hope this was of some help to you.
Also, if you are interested in IntelliJ IDEA plugins, please check my earlier post which lists down all the IDEA plugins which I use.
Update on 05th April, 2015: After a fair bit of time here, I have moved on to GitHub hosted Octopress blogs. Please find me on http://P7h.org henceforth for all new updates.