Unison

I've been plagued by the fact that at work I do my development on a remote system. This generally isn't a problem except on the rare occasion I want to use a debugger, since I'm a Vim user. However, when that time comes (and it always does), I have to sit there and wait while eclipse "builds" my project. Nothing irritates me more than "Hurry up and wait". Since I started working with Drupal, I've found this to be a very common theme. It's far from the speed that I got out of Zend Framework, or other MVC based frameworks, but it does so much for you.