Assuming that that java bash was in context, I have to say that the IDE features I mentioned would be useful for almost any language:

Refactorings: I can rename a method in one location and it will change all the calling code. This would be dangerous to do by hand: Best case scenario, there would be a compiler error for all the broken code. Worst case, that method name was already overloaded and you just introduced a bug.

ctrl+n: Open any file that's in your project. It can find the file by camel case or pattern matching and it only includes files in your project.

ctrl+alt+h: See a tree of all the callers of a method. Extremely useful when you're considering a refactoring. You can instantly answer the questions, "Is anyone calling this method?", "Is anyone calling the methods that are calling this method?...", "What will be affected by this change?", and so on.

Although not as comprehensive as the eclipse refactorings, ctags go some way towards giving you similar functionality in vim.

There are Vim emulation plugins for Eclipse, if you want the best of both worlds.

And don't forget eclim, a Vim front-end for Eclipse (or an Eclipse back-end for Vim):

http://eclim.org/

Sounds exciting but a little scary. Have you used it?

I have used it in order to develop an eclipse plugin for vim. It took some time to set up, but then it worked as advertised. I could use vim inside eclipse. It exposes all the mistake detection and completion stuff of the regular Eclipse editor, but triggered by keybindings instead of automatically.

Not exactly. I tried setting up a really complicated system with Eclipse running as a server in a VM and my local Vim serving as the head to it, but haven't gotten that working yet.

I prefer Vim as the frontend, but was hoping to add Eclipse's code correction and refactoring to it. But that's also the most complicated of the three options, and least well supported right now.