Silverlight 5 RC is out

Silverlight 5 RC is available for
download (Yes, I know, I'm
a little late).
Silverlight 5 introduces some interesting features, including the following:
- P/Invoke (woot!)
- Custom MarkupExtensions (yay!)
- Implicit DataTemplates
- Ancestor RelativeSource binding
- Binding debugging
- Multiple OOB windows
- 64-bit plugin
This release candidate marks another step towards SL/WPF feature parity. WPF developers are now at greater liberty to utilize their tried toolset within the (relatively) new framework natively, rather than resort to various workarounds (Arik's our own!).
As Tomer and I are actively trying to convince a customer to move their (nonexistent as yet) WPF client to Silverlight, this is great news received just in time!
Update: Pete Brown has a full list of Silverlight 5 RC features.