I tried a few of the LaTeX editors for OS X. TexMaker, TexWorks, TexShop and TextMate/BBEdit offer syntax highlighting and some additional features to edit single tex files.
On Linux I've been using Kile for LaTeX editing. The outstanding feature is the 'project' mode, which opens a project view with a side pane. You can open several tex documents and save them in a hierarchical folder structure and thus split your chapters up in several files with a main file where you include each chapter. You can also add images etc. It's much like an Eclipse project. That's very useful for large projects like a thesis or research paper.
Question: Is there a LaTeX editor for OS X that offers similar options?