Remoting. With the rise of Indigo, there are a lot of questions about Remoting, it's long term applicability and future directions. We (as in Microsoft) have been perhaps a little too clear in saying that Remoting will be "depricated" with Indigo ... but less clear about explaining what that means. That statement also leaves some really unnerving questions about applicaitons developed using Remoting today.
So ... here's the definitive word on Remoting's future: http://blogs.msdn.com/richardt/archive/2004/03/05/84771.aspx
Note the guidance for the use of Remoting today, the limitations of Remoting migrating to Indigo (in particular, custom channels and sinks). Note, however, that the functionality of Remoting, the classes and namespaces, will still be in the framework for the forseeable future.