I will not explain in detail the eclipse plugins you obviously try to get like subclipse, or other eclipse plugins that helps you with your current language like PHPclipse for php, etc.
I focus on the eclipse plugins that helps you with small problems and make your like easier on a day to day basis.
- FindBugs for static code analysis in Java. Reviews the code and shows problems with solutions how to fix them.
Update Site: http://findbugs.cs.umd.edu/eclipse/
- QuickREx for evaluating regular expressions as you type. This helps to create these expressions in quite some way.
Update Site: http://www.bastian-bergerhoff.com/eclipse/features
- OpenExtern for opening a folder or file using the shell or the explorer
Update Site: http://openextern.googlecode.com/svn/trunk/openextern_update/
Maybe this also helps you during your development of your solutions.