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
if you are looking to remove the sluggishness from the app, memory management is obviously important. besides increasing the maximum heap settings and other command line tinkering, there have been eclipse plugins developed in the past that claim to prevent windows from swapping out eclipse RAM. 'Keep Resident' hasnt been updated since 2004, but it is still on the eclipse site and i have heard tell that it works with 3.4. a review is written here