What is the single best free Eclipse plugin for a Java developer

Answering my own question with my current favourite, Jadclipse, which works with jad to disassemble class files from third party libraries.

http://jadclipse.sourceforge.net/

Subclipse SVN for eclipse Update URL: http://subclipse.tigris.org/update_1.4.x

If you need to get more insight in your code coverage EclEmma is pretty straightforward and useful

http://www.eclemma.org

Findbugs saved me doing something silly twice today.

http://findbugs.sourceforge.net/

Eclipse update site is: http://findbugs.cs.umd.edu/eclipse/