This caught my eye because it's the exact same thought process that lead me to reboot my blog using Jekyll a few months ago. Brent Simmons correctly identifies the two different ways you can go about doing this. He notes that, to gain wider adoption, somebody needs to make this method easier to use:
It should be as easy-to-install and easy-to-use as WordPress — easier, actually, would be better. Not-requiring a database at all would be awesome
A database can lend itself to some nice functionality, but for the majority of WordPress-driven sites out there it's overkill.