You know, it's really late, and I should be asleep, but I was completely mesmerized after downloading and installing this really cool WPF-based family tree application from Vertigo called Family.Show.  It was showcased at MIX'07 this week, so (not being there myself) I had to download it and check it out.  I'm totally impressed with the application.  As they say on their web site, they totally pulled out all the stops.  The app is really responsive, has excellent graphics, and a really "it just makes sense" UX.  This is definitely one to check out!