I am always on the look out for a great IDE and for the price (free) NetBeans is truly one of the greats, for any web dev. It has great code completion and even lets you define custom code completion for things like CodeIgniter. Where the loading stucture tends to confuse standard code completion methods.
As I said it truly is a great IDE unless of course you are on a Mac. Unfortunately do to the way they package their executable in OSX, NetBeans cannot open a file from finder. Meaning if you open finder and double click, or select open with NetBeans on a php file or some other code file NetBeans will start if it hasn't already but will never open the file in question.
Now 70% of the time this isn't an issue using the tree view project structure on the left to open your files in your project is pretty basic and straight forward, but if you ever need to open a file out side of that you are forced to use File -> Open menu options on NetBeans, something I think hardly anyone does and something that is extremely annoying.
After having a bug ticket on this open since 2008 myself and a few others finally got enough attention drawn to the matter to get it escalated to have someone look at it. So a month or so goes by and finally the results are in: Closed, Wont Fix.
Now I do understand why they wont fix the issue. Who in their right mind would completely rewrite some of the base code of their project just to handle an annoyance in a single OS? I know I wouldn't, and I can't blame them for that either. It just sucks that this issue is annoying enough to me that I am now looking for a new IDE in OSX that can handle the "magic" of CodeIgniter. Currently I use Komodo Edit which does an alright job, but lacks many of the great features of a true IDE, and no CI code completion, or debug support.
My requirements for a good IDE are, debug support, subversion support, CI code completion, a good find/replace implementation, and works in OSX obviously. I have tried Eclipse but its bulk tends to leave a bad taste in my mouth before the program even finishes loading. That may be my only option though (sad face)