CVS, Subversion, Mercurial integration: I use it e.g. to synchronize the chapters of my current book with oreilly.
JavaScript editor / debug supportFavorites: The ability to browse the file system and edit files. NB can be used as a generic editor.Services: Great database viewer with paging, inline editing etc.UML support (additional 7MB plugin): really good tool for creating overview diagrams etc. I used it to illustrating my recent books and articles. I saved a lot of time :-).Java FX support (additional plugin): compiling, debugging, auto completion, draggable applets, web start etc.Diff functionality: you can diff any files you like. [I forgot this point in the origin post :-)].
...and Groovy, Grails, PHP, Scala, Python support - I do not use them, however, in my current projects.