>>>>MySQL and Postgres are free, last I heard.
>>>
>>>Interestingly, a new player in the PB-class DB field is based on PostgreSQL: http://www.dbms2.com/2008/08/25/greenplum-is-in-the-big-leagues/
>>
>>Yeah, and I've been interfacing with Firebird a little bit recently. Lots of options. M$ is still the extreme heavyweight in this arena, however.
>
>Have you seen any recent market share figures? For many years Oracle basically owned the SQL RDBMS market with DB2 having some share. Then Sybase/MSSQL got a toehold, MS poured in resources and the last I saw MSSQL was neck-and-neck with Oracle.

I don't know exact figures, but I believe M$ has the largest share. My "heavyweight" comment actually stemmed from their general dominance of the market, which tends to make percentages creep in their favor over the long run. Sorry I wasn't more clear on that.