Сразу скажу что много всего, но остановлюсь на расширении для разработки под мобильные телефоны.

•  New Integrated UI for CLDC/MIDP and CDC development. 
  The Mobility Preview now supports the project properties previously available only for CLDC/MIDP projects. These include project configuration support for device fragmentation, integrated obfuscation and optimization support, and multiple deployment options, all built on Apache Ant for easier coding and management.  
  
•  New game builder. 
  Now it's easier to create mobile games with the Mobility Pack's visual editing support for the MIDP 2.0 Game API. The API supports animated sprites and the ability to arrange tiled layers into scenes. 
  
•  New Visual Mobile Designer. 
  The Visual Mobile Designer (VMD) has been re-designed for improved functionality and usability. 
  
•  Design analysis. 
  Design Analysis identifies unused components for removal from complex visual designs . 
  
•  New custom components. 
  New components for the Visual Mobile Designer simplify the creation and design of mobile file browsers, Short Message Service (SMS) composers, login screens, and Personal Information Manager (PIM) browsers. 
  
•  New components for Flow Control. 
  
•  Generated code is now easier to modify. 
  
•  Re-written JSR-172 stub compiler. 
  The new generator has support for Base64 type and is able to parse documentation from methods. 
  
•  Improved project configuration management.
  A new UI for the Project wizard makes it easier to add new project configurations for new mobile devices. It's now easier to create multiple builds for multiple configurations.

Более подробней Вы можете прочитать на официальном сайте:
http://www.netbeans.org/community/releases/60/index.html

Ну мне например Visual Designer очень понравился, когда я наконец с ним полностью разобрался.