OneLine: Database Systems

http://iamwww.unibe.ch/~scg/FreeDB/FreeDB.home.html 
List of Freely Available Database Systems

ftp.uni-trier.de
Great Archive

Best big and complete relational (SQL-driven) database: Postgres95
Best tiny and mostly complete relationa (SQL-driven) Database: mSQL
Best fulltext retrival system: Glimpse