[Decent12]

I think that the most useful IDE for Java is IntelliJ. It support a lot of framework and it very extensible.
NetBeans was decent enought but when Apache got the ownership over it I saw a very slow development: netbeans was one of the faster IDE to release a version compatible with the latest java revisions but it is not like that anymore.

IntelliJ comes both free and commercial edition. You won't need commercial edition for the start level/common development. Maybe you could need the commercial one if you are doing enterprise programming.

Give it a try and let me know.

I just gave a try to IntelliJ after watching all of you opinion and used it almost a month but the thing i noticed in IntelliJ its fast but the error reporting is not good as netbeans i have made couple of mistakes while using IntelliJ it went un-noticed while if you do the same in netbeans it wont let you go forward unless you correct it.