NetBeans 4.1 beta: UI builder, etc.: wow!
The NetBeans 4.1 GUI builder is intuitive and easy to use. I like the new project views also. I usually use IntelliJ, but have been using Eclipse more recently because of useful plugins for C++/Ruby/Python development, semantic web, etc. Anyway, having three great Java IDEs (2 of them free!) is great :-)
If for nothing else besides the GUI builder, NetBeans is a great addition to my working environment. When version 4.1 is released (non Beta) I will try to get some time to 'kick the tires' of the web app support also.