What "Log On" should I use on a SQL Server Express 2008 running in my workstation for the purpose of development if I want my local windows user to be just recognized?
The options I see are "Built-in account" which let's me choose between "Local system", "Local service" or "Network service". The other option, "This account" seems to allow me to specify a username and a password but it seems the user is picked from the accounts on the system, I'm not sure.
For local development you can use Local System and that should be enough for you to do your development.
If you are going to use a desktop client, then I would use Network Service.
Again, this advise is for a local development server, not for a production server where MS best practice is a domain account setup to login as a service.
Update: By desktop client i mean you develop a application that uses SQL Server as its back end and runs on a different computer and uses the network for communication
I think you might be confused here about what the service is. The service account runs the SQL Server database service, and that is what logs onto your computer and then accepts queries from a client.
The windows user you use to "logon" to SQL Server is a "login" in SQL Server. You authenticate separately to SQL Server, just as you log onto Windows. By default the local administrators on the machine (BUILTIN\Adminstrators) are added as logins to SQL Server, so you can access the server and run queries, add data, etc.
If the SQL Server service needs to access the network, then the Network Service is recommended. If not, Local Service is the choice recommended.
If your SQL Server needs to get to resources on other machines, then you typically create a domain user, and use that as the service account.
