The question dealing with Visual Studio optimizations saved me so much time firing it up and using it I have a hard time going back to Eclipse when I have to do J2EE develop
The biggest optimization I've found for Eclipse is turning off Theming. My very minimal installation was extremely slow, so I wasted a ton of time doing all the debugging steps until I finally unchecked "General > Apperence > Enable theming" and everything got much much faster. I also put -server in my eclipse.ini, but, the biggest trick was just turning off theming (with much much sadness).