No. The question itself makes no sense at all. WCF and Windows Service are not different options. You can use WCF with Windows Service and without it, self-host WCF in Windows Service or not, you can also use Windows Service without WCF, using sockets, classical remoting, named pipes or anything else for communications.
These two concepts are not related. Windows Service is a type of application which is hosted by the service host and runs in non-interactive mode; in this way, it keeps running when users log in and out or in nobody logs in. WCF is well… a Foundation, Windows Communication Foundation, a Framework and API which can be used in any type of applications, no exclusions.
You have to read at least just a bit before asking such questions. See:
http://en.wikipedia.org/wiki/Windows_Service[
^],
http://msdn.microsoft.com/en-us/library/d56de412%28v=VS.100%29.aspx[
^],
http://en.wikipedia.org/wiki/Windows_Communication_Foundation[
^],
http://msdn.microsoft.com/en-us/library/ms731082.aspx[
^],
http://msdn.microsoft.com/en-us/netframework/aa663324[
^].
[EDIT]
Here is a step-by-step advice of how to self-host WCF:
http://msdn.microsoft.com/en-us/library/ms731758.aspx[
^].
If you need something else, you have to explain it. If you don't have any special requirements, I would recommend to self-host.
—SA