Apple's Xcode

There are very few conversation-worthy code editors for OS X. Most code editors for OS X provide rather simple functions, but not enough capability to handle larger volumes of code and a multitude of files. Luckily, Apple offers Xcode (external link) - an integrated development environment that can handle a wide variety of programming languages - which is included freely with most Macs.

Xcode is intentionally for OS X programming - Carbon, Cocoa, etc. - but it also works well with web programming languages such as PHP and Perl. Xcode's true ability shines when it is used to program larger projects, using languages such as Java and C++. For the simple PHP programmer there are no particular advantages to using Xcode; however, it is a working, easy-to-use code editor that you can obtain easily and for free.

If you are on OS X you may want to give Xcode a try, over your current code editor. I myself recently switched to Xcode, over Smultron (external link), because its PHP highlighting is more accurate, where Smultron had some odd flaws in how it highlighted code.