Soma has just announced that C# will support Edit and Continue in Whidbey.
Waaay back when we first planned Whidbey, one of the questions we asked was "is refactoring or edit and continue more important"? We knew that our users wanted both, but we didn't have schedule time to do them.
The answers we got back were along the lines of "refactoring, but we'd also like E&C as well".
At the time, it was an either/or choice, and we did refactoring. After talking with customers at the last PDC, it was apparent that the desire for E&C was pretty high. We explored if there was any way to do E&C in Whidbey, and came up with a way to make it happen. And now, thanks to the hard work of many on the C# team (excluding me, who didn't really do much of anything), the feature will be available in the next community preview.
So why didn't we tell you earlier? Why did Eric lie to you when you came up to him at TechEd and asked about E&C?
Well, the fact is, it was a very near thing. If a few technical details or schedule points had come out a bit different, it wouldn't have made it into the product. We decided to delay announcing until things were firm rather than risk having to de-announce a feature.