Which free database would you use for a relatively small datawarehouse system?

Are there any 'special' databases e.g. multidimensional databases freely available?

Which of the free relational databases is best suited for the job?

By datawarehouse system I mean a system that will receive some inserts, few updates, next to no deletes and plenty of complex selects. Structured in star schemas (if the database is relational).

By small I mean about 100.000 records in the main fact table, maybe 10 dimensions, the largest containing 5.000 records.

Be free I mean free of charge of internal commercial use.