>>- Postgres has a much richer built in function set.
>Partly true, but you can't add functions to Posgres like you can
>Firebird, so some of my local Firebird stuff can't be ported to it.

I guess I must have imagined this part of the Postgres manual then ;-)
http://www.postgresql.org/docs/7.4/interactive/xfunc-c.html