I suspect that PostgreSQL isn't a trivial piece of software, and I consider it among the greatest of all FLOSS. It even bills itself the most advanced of all FLOSS databases. That's what brought Martin Pitt to my attention, for he is it's Debian (and now also Ubuntu) maintainer. One other notable thing about him is his quiet persona (I follow Debian development fairly closely, and I don't remember seeing him take part in any of the arguments in its mailing lists). I only ever notice him when he'd give some random status update.