Please understand, this is for your information not to start any IDE wars. I'm sure you each have your own favorite IDE, and some of you will prefer to die defending it rather than admit there is any viable alternative.
Personally I have to be IDE agnostic because I have to use whatever my customers are using - though surprisingly often now there is a choice. It used to be that when I went consulting, a site would have mandated one IDE, and there was a big process which they went through to select that IDE (you could tell because it left visible scars on some developers). Nowadays, almost every site I get to has no mandated Java IDE, instead you
can choose one from a list - or whatever you want in some cases - as long as you can
integrate it into the existing development process.
I went to a lot of different sites over the years. It used to be the emacs IDE guys who were the loudest about how great their IDE was. Nowadays it is the IntelliJ guys. And I do mean guys, none of the female developers I met used to spout on about her IDE being the best.
I have been using for a while CodeGuide, a Java IDE from a German company, that really improves productivity in comparison with most of the others mentioned. In some respects may not be as generic and complete than others but with complete project analysis on the fly, showing the impact on the whole project as you type, hot swap debugging, froward and backwards in expression debugging and a very good refactoring function my productivity really improved in comparison with the other IDEs.