Asynchronous and concurrent programmings seams to be on everyones minds these days and .NET 4 adds a number of improvements such as built-in thread safe collections and of course tasks. On top of this I've started looking at the Reactive Framework (Rx).
Tasks appears to be primarily more focused on concurrency for computation performance although it's also a general model for operations that will complete some time in the future and can be used handle other types of asynchronous operations, as well as combining them using .Continue*(). The Rx appears to be more useful for reacting to multiple events and stateful event handling.
Do you see an overlap between these two frameworks and specifically, do you see a use for modelling am IObservable in terms of a Task and vice versa?