I will be starting a web business soon. We would be providing some directory services on the long run. I would like to know what do you guys think is the best choice for middle tier and backend database solution.

I am thinking of using SQL server instead of VFP database. Any comment? Also, I am not sure if I should use VFP to build the middle tier. It may not be a good idea to go 2 tier first because we aim for large transactions.