PostGIS absolutely deserves some attention, as it's one of if not the best GIS DB out there. It felt too big to include in here, but I should at least add some small callout.

Thanks for the article! I started using postgres because of one of your slide decks and I've learned a lot from your writing over the last year or so.

PostGIS is awesome... the geometry functions built into vanilla Postgres provide an interesting set of functionality that almost no one seems to know about. points, boxes, circles, intersection/distance/etc functions. Really cool stuff!

http://www.postgresql.org/docs/9.3/static/datatype-geometric...

Also worth mentioning that a lot of people go for PostGIS when really they just need the earthdistance module. Much more lightweight and very very useful.

Hadn't heard of it, thanks for the tip. PostGIS really shines when you need to manipulate geometry.