Even as a heavy PostgreSQL fan and promoter I don't see why you would choose anything BUT sqlite for single-user applications unless you needed something that o

Even as a heavy PostgreSQL fan and promoter I don't see why you would choose anything BUT sqlite for single-user applications unless you needed something that only other databases provide (richer procedural language support or other extensions that the fairly basic but still adequate featureset SQLite provides) - size of the dataset is only one factor to consider when choosing the storage layer for your application, and there's a lot of valid solutions for handling 1TB or less of data easily.