I have a new WCF Service Application, when I hit F5 to debug, the WCF Test Client always comes up, but I would like to disable it since I am using soapUI to test instead.
A simple option that works for me (at least in Visual Studio 2012 Update 4):
Open the WCF project properties and go to the Web section. Set the Start Action setting to Don't open a page. Wait for a request from an external application.
After choosing that option I no longer see the WCF Test Client.
I personally usually choose this start action anyway, since I much prefer hitting F5 in my browser than having yet another tab opened each time I hit F5 in VS.