Re: CraigN's question on what content would be best.
I'm not going to make the Mix Essentials talk, so a "repeat" talk would be great for me. I'm really keen on something "hands on" so the "walk through how to build a Silverlight application end-to-end" part of the talk is probably the best. So far I've only seen botched/badly delivered demo's of building silverlight applications "end to end". I'm also keen to see a bit more about how Silverlight v2 is different from v1. I.e I don't really care that the UI can be flashy, I want to see the .Net backend/"code behind" goodness that's been added.
But that's just me... not sure what the rest of the attendee's would want.