Autocomplete was not working for JSF tags in my Eclipse. I googled it and finally found the solution on http://www.mkyong.com/jsf2/how-to-make-eclipse-ide-supports-jsf-2-0/
Thanx Mkyong.
The different thing I did is; I downloaded javax.faces-2.xx.xx.jar and saved in a specific folder. Then I created a user library with this jar. I did not use “jsf-api-xxx.jar and jsf-impl-xxx.jar“.
Akdora's Blog 
I think you should selected template while you create new a “JSP” file in step “Next” choose any “New Java Selet Face(JSF) Page …” and Check Goto Windows–>preferences–>General–>Editor–>File Associations then choose a File Types: “*.jsp” and “*.jsf” then see below Selected Associations Editor “Web Page Editor” then click “Default on the right .
See following for suit yourself. http://stackoverflow.com/questions/54868/what-is-the-best-html-editor-for-eclipse