Question: What version of Eclipse do I need for Google Web Toolkit? I see about 7 versions, but none make any references to GWT. Google doesn't mention it to. I did install the PHP version.

Answer: 
Definitely the Java EE version. The regular java version doesn't seem to work with the google plugin.
Since GWT means Java programming I would recommend the Java (default) Version of Eclipse or Java EE Version because they contain the Java Development Tools which will help you very when coding in Java