What is the best local-database solution for WPF applications?

Question

What is currently the best solution for WPF applications which are meant to be used on one computer where various users log into them and use t

Answer 1

SQL Server Compact edition is also an option - http://www.microsoft.com/Sqlserver/2005/en/us/compact.aspx

Deployment is pretty easy using ClickOnce or by copying the engine dlls to the application directory.