Best Practices - Securing an Enterprise application using JBOSS & Postgres

What settings would you recommend for using postgres in an enterprise
application together with jboss?

there are numerous auth options (from the documentation):

19.3.1. Trust authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#AUTH-TRUST>
19.3.2. Password
authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#AUTH-PASSWORD>
19.3.3. GSSAPI authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#GSSAPI-AUTH>
19.3.4. SSPI authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#SSPI-AUTH>
19.3.5. Kerberos
authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#KERBEROS-AUTH>
19.3.6. Ident-based
authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#AUTH-IDENT>
19.3.7. LDAP authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#AUTH-LDAP>
19.3.8. Certificate
authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#AUTH-CERT>
19.3.9. PAM authentication<http://www.postgresql.org/docs/8.4/interactive/auth-methods.html#AUTH-PAM>
and i'm not sure that the jdbc driver even supports all of them when jboss
needs to access the db.
currently i've chosen MD5 as the auth, but is that the best option?
thanks
Eyal.