Database needs to be stored on the local machine, which rules out SQL server express & CE.

Local databases that i know of:
Access (Free-little security)
Sqlite (Free-Moderate security)
Oracle Express (Free-security ?)
IBM DB2 (Expensive-good security)
Others.....?

So if you had an application that made you $40,000 per year, what database would you use taking into account security.

I could possibly look into an online database, would this be practical/fast when 50 rows of data are pulled at once (currently takes a split second)?