I’ve succumbed to the temptation of joining the argument about Hibernate and OFBiz’s Entity Engine.
Mike used the Entity Engine with JIRA. I have done a bit of hacking with it, and it hangs together quite nicely. That said though I think that WebWork and Hibernate would make for an even better match.
If you are Hibernating and then decide you really need to use EJB’s you could always swap them in. (you don’t really want to do without value objects do you?).
One of the cool things about Hibernating is that you get ctrl-space etc in ide’s.
Dynamic Typing is cool and all, but I like the idea of using an IDE to help me remember what attributes are available.