Role Models Wanted

I'm searching for projects that would serve as good PostgreSQL examples. In
fact it would be nice to have a place on the PostgreSQL web page that
featured some good examples. (If such a place exists and I missed it, please
let me know.)

Ideally the project would have the following characteristics:

-Open-source (naturally, it's hard to use as an example otherwise)

-Good database structure/normalization

-Good error detection/recovery

-Appropriate use of back-end capabilities including functions, triggers and
rules

-Good security practices

-Appropriate use of special PostgreSQL features (non-standard data types,
inheritance, etc.)

A single project might not fulfill all these requirements so feel free to add
personal comments or warnings, eg. "Check out the foo project. It is a PHP
based snarf tracker with a very good database design and extensive use of
PL/PGSQL functions. Don't emulate the security, however, since the code fails
to check for dangerous input leaving it vulnerable to SQL injection attacks."

Also feel free to add characterstics to my list.

Cheers,
Steve