I prefer files for application/admin configuration and DB for any user controlled configuration (most of the time). Files are safer for an application because you aren't relying on (at least) two services (your app and the DB) to run your app. Configuring from files allows the application to run "normally" (in reduced service mode or something) even when the DB is unavailable. Of course files can become unwieldy so the DB is (like mentioned already) better for many other things (that will grow, require constant update, fit into a standard API, etc).
