Given your background in .NET but limited Asp .net experience... I assume you are more of a service/client guy. Which will mean your javascript is probably just as limited... If this is the case, I'd go with Silverlight. It will ease you into WPF, which you may be likely to use in the future.
But more importantly working with Silverlight 2.0 feels more like building a sandboxed desktop application. More than a web application. You will be more at home with Silverlight if your prior experience is with client apps.
If you want to break into building web sites/applications go with ASP .NET MVC.
Either way knowledge of the typical ASP .NET controls will not go far, since they are for WebForms.