Silverlight leaves the browser behind! This is what I've been waiting for. Silverlight now effectively has all the parts & features I want to effectively rule out the need for Flex, Flash & Air. With Silverlight moving outside of the browser we provide, finally, a true speedy application for RIAs. Of course, yeah yeah yeah, Java did this over a decade ago, but it did so poorly. Silverlight is FAST. I'd gather it is faster than Air, and possibly faster than Flash in the majority of measurable ways.
Now the big question that remains, is what will happen to WPF. This significantly decreases the need for WPF for use as a web connected apps framework. WPF is now relegated to only Windows. WPF seems like a less viable platform than ever with Silverlight being enabled in and out of the browser, at least for LOB business apps and that ilk.