I've been looking at several tools for this venture. Delphi is a requirement as I can deliver a great application to the intended audience using Delphi. I've looked very seriously at both Firebird and ElevateDB as the intended database that I will be using. I still have not made up my mind on these yet as both have their strong points.
If I end up going with Firebird, then I'll most likely be using the IBObjects components. I've used these before at a customer's site and have been impressed at the genuine speed that results.