@Ian2: I'd heard that the SDK was leaked and developers could glean nothing out of it that we didn't already know. Heard this on one of the Twit podcasts, and have done nothing to verify it, but if true, I think Microsof has blundered very badly here by not having an open RC.
@PeterF: We know there's much better Portable Library support all the way around coming. It's one of the things I'm most interested in. However, there's no information if any of it will be compatible with WP7. In particular I was told that contract support was coming, but despite direct inquiry I've not been told if this includes WP7 or is only there for WP8.
Edit: Just noticed I said "better Async Library support" when I meant Portable Library support.