Pardon my chime in:

Its singular, as in the WS standard only allows you to create ONE endpoint for a "WebService" regardless of how good bad the devs coding skills are wrapping a class..

A web service is a interface, as all the definitions in your WSDL doc (remember that?!) are abstract definitions of the portType you will bind to your messages and datatypes, wherein you will implement that as a class, (pardon me Bill:  Enterprise Java Bean), or COM object wrapped with a type library. (Ah the foolishness..)

There is an eventing model and it is parser-based, as in SAX or DOM (and obviously eventing is more the SAX event-driven model than the DOM tree-model.)

Oh yeah, not to mention that although you can bind to multiple ports you have complete control on the bindings, and it can be run-time dynamic too, as well as allow you to implement other standards besides SOAP (check out the Apache (bad word right...) WSIF (Web services implementation framework) and GlassFish projects.  VisualStudio is but a mere TOOL and not the defacto is all, has-all, and so there is SO much more to A WebService under the hood.  This is no matter how well you architorture your application.

Essentially the engine underlying the abstraction is a stub, but it is so much more than RPC.. and the whole idea is to use the internet as the vehicle (much like VPN, o why use sommething other than http?) and have standardized, well-formed interoperable xml flying around (sounds like the basis of the framework itself huh?)

So my vote is Singular. and interfacey, and enterprisey, and how about those Seahawks?

On another note, I think us self elf-policing the community is a bad idea if so many of you dont even understand web services. Cool So flame me, you can't always have things your-way. haha

After all is said and done though, this is a great question, but it won;t makke you any sexier than you already are (not).