Do checkout Microsoft LightSwitch http://www.microsoft.com/visualstudio/en-us/lightswitch
The simplicity which allows to create ntier apps is simply amazing. It uses Silverlight as the UI, Code First Entity framework for data access and WCF RIA services as middle tier.
You can accomplish many things without writing a single line of code. Also, the default out-of-the-box functionality doesn't suits you it provides highly customizable interface.
Do watch the how to videos here http://msdn.microsoft.com/en-us/lightswitch/gg604823
You can utilize you exiting silverlight, wcf, RIA knowledge an accomplish much more in less time and it perfectly suits intranet kind of environment as well. Do give it a try before writing this off :). Thanks.
Rajesh Pillai, Mar 24, 2011
This is an interesting question. Here is my views....
If you are having only Silverlight client in your intranet application, and also it of smaller or mid sized application, then you can go for RIA services.
Otherwise, if you are having multiple clients other than silverlight, then WCF can be used in the business layer so that any of the business services can also be exposed to outside world using different bindings. Architecture would be Silverlight <--> WCF [Businesslogic] <--> Entity Framework ADO <--> DataBase
Vivekananda P, Mar 16, 2011