Gathering some Libraries

Hey,

So I’ve never really made serious games with Java before. I’ve made simple things like Pong remakes or asteroids or tetris, and other silly things like that. I’ve messed with slick2d a bit, so I’m kind of comfortable with the basics of that. So my question is - what other libraries should I collect to get started? What do I need and what’s available out there?

Slick2d
something for gui? (other than twl, if possible)
something for physics?
something for networking?
other ideas or suggestions?

Thanks for any help.