I've been enjoying the latest 3.0 M2 build of Eclipse. A week ago I was pair programming with Mauro Talevi adding JMX support to PicoContainer (in the NanoContainer project) and I picked up a couple of Eclipse tips in the process.
* I'd never understood what this did before (DOH!) but the Window-> Switch to Editor menu item allows you to quickly close all (or most) of the editor windows very easily. e.g. select all the editors except the current one or two you're interested in & close all the rest
* there are various XML editing plugins available (X-men, xmlbuddy). Though for simple stuff, just enable the Ant plugin for all XML documents. The Ant plugin has a simple colour coded XML editor.
To enable it, open the Preferences window (Window -> Preferences) then go to Workbench -> File Associations.
Then for *.xml add the Ant plugin association.