I'm most excited to see MP6, Widget Chooser Plugin, and hopefully, Twenty Fourteen in 3.8. I'm stoked about Twenty Fourteen and curious to see the wide array of editions of the theme people make with it. As for Widgets, love the fact that I don't have to solely rely on drag and drop to add or subtract widgets. That's a huge plus. MP6 has made the admin easier to browse and read.

All of this combined will have 3.8 being a great release.