Here is a very extensive list of "Free" databases. This list was but together to give developers the rightr choice over poorly used items such as flat files, personal (desktop) databases etc... Also to show it does not cost $$ to give you the power of some costly database servers. Although there are limits to these free db's, they are powerful and should be utilized over methods that cost valuable performance.
Keep programming the right way and happy sleepless nights doing it! :)
Special thanks goes to damber, SQLDenis, Tarwn and stefanwagner for building this list and finidng the links.
Note: please report all broken links via the "Send a Comment to onpnt About This FAQ" link. Thanks for helping to keep this list updated.