I currently use Eclipse but am looking to try out some others. What's the best?
I think, you cantry the JDEV from oracle. With this IDE you have all support for java and J2EE
NetBeans is free (open source) and has a credible list of features. You can also download modules from the net for extra features like unit testing, database browsing, etc.
Sun ONE Studio 4 (based on NetBeans, used to be called Forte for Java) is also good, but only the Community Edition (basic) and Mobile Edition (some kind of Sun Wireless Toolkit plugin) are free.
I am happy with Eclipse 2.0.1
Why not try pivotonic JawaBeginer?
It is very similar with UltraEdit and add more other functionalites for Java programmer especially begingers.