Mark Shuttleworth's recent post about the planned Ubuntu Heads Up Display has stirred up a bucket load of interest. See here for what it looks like:
Name apart, I like the look of it, quite a lot. And I think that's because it's a very good idea I already use: the keystroke launcher GNOME Do, and the command palette in the glorious Sublime Text editor.
What I find interesting is that this is a keyboard feature, not really a touchy-feely thing.
Looking forward to trying it out for real :)