Sublime Text

Download: Sublime Text + Sublime Text Haxe package

Sublime's Haxe package has excellent support for Flambe out of the box.

Once installed, just drag the root folder of your Flambe project into the Sublime icon, and it will recognize it as a Flambe project. Open a .hx-file and use the Control-Shift-B keyboard shortcut on the Mac to select your desired build target. Then, hit Control-Enter to compile. Sublime's Haxe package gives you great auto-completion, snippets and code hinting.