I can't believe you guys who are recommending WSAD. It's a memory hungry and slow POS. I only use it because I convinced my boss to shell out a couple thousand dollars for it and I would feel guilty if I didn't use it. Plus at the time it was the only thing that would allow me to debug my application running in Websphere. I have two machines at work at my disposal, my laptop (P-M1.7Ghz, 1.5GB RAM) and my desktop (P4 2.8Ghz, 2GB RAM) and both get bogged down easily.
That being said, if I had to choose again, I'd look at Idea or even Netbeans. Eclipse won't have full J5SE support for a couple more months. The latest Netbeans has it now although it's still in beta.