Middle tier - C# class library or WCF?

I am developing a new business application which will require a business layer and a data access layer.

Right now, I have both of those as simple C# class libraries which will be consumed by a Silverlight RIA app and a WCF app (which will be exposed as SOAP web services).

Is there any downfall to developing these tier开发者_JAVA百科s as a C# class library as opposed to using a WCF library?

So, instead of Silverlight->RIA (ASP.Net)->BLL C# class library->DAL C# Class library->EF->SQL Server

would it be better to go Silverlight->RIA (ASP.Net)-> | (web) | ->BLL WFC library->DAL C# class library->EF->SQL Server ?

A normal C# library is good enough. Your web project can still handle your wcf service configurations for you. All a WCF library does is reference wcf libraries in it when creating it.