What are the best practices in developing rich UI extensions for ASP.NET MVC (I mean asynchronous / partial loading, slick effects, skinning etc) ? I saw that Telerik has an MVC suite of extensions, but haven't tried them yet, so I cannot comment on them.

My biggest concern as of the moment is how to structure the code of my extensions so that C#, ASP markup, and JQuery remain separate from each other, yet encapsulated in a way that the extension must be easy to distribute and reuse.

I know that the user control approach had many flaws, yet it sort of allowed application developers to just reference a control, set some parameters and get it going in a few minutes. I'd like to achieve the same kind of portability/reusability as I still keep the code easy to extend and build upon.

Now, some ideas that come to mind as topics for discussion are: template helpers vs. extension method helpers or a possible integration efficient use of jQuery - naming conventions - - asynchronous action loading - etc you can add whatever comes to your mind