I have been in the projects that JSF,EJB3 and Seam have been the core technologies and frameworks. But I can't actually call them completely enterprise.
I don't know especially how much seam is reliable to be used in the enterprise  applications. Is it performing well out of JBoss? Has it been used some where well known like amazon or ebay,..
Also about JSF, Have you tried ICEFaces? How relaible is ICEFaces? What do you suggest?