There are lots of tools out there for Hibernate, Which one are you using:
Middelgen,
HibernateTool
PowerMap
Build in class2hbm, hbm2java and ddl2hbm
HiberClipse

Or you prefer hand coding.

I am working on HibernateTool (http://www.hibernate.org/255.html)
which seems to be good. Take a look at
www.hibernate.org/.../hibernate-eclip\
se-news-3.1.0.beta1.html)
which contains the latest features of this tool, entity model seems to
be a great feature.

The main problem of almost all above tools is that, they are Eclipse
plug-in and you will force to use this IDE. I am not familiar with it
and I don't know if it is as intelligent as IntelliJ Idea. (Does it
support JDK 5.0 features?!), Please correct me if you have good
experience with this IDE.