For me, Libreboot and Replicant come to mind.
They are both so damn important and have severe problems (replicant doesn't
support a single device with working wifi, libreboot is limited to very few
mainboards).
Besides, I immediately think of reverse engineering of wireless card
firmware.
I mean that's one of the biggest obstacles for most users, right?
And yeah, a skype alternative (we have many things that come close, but we're
not all the way there).
People tend to use more and more smartphones and tablets. The situation there
is horrible to say at least.
Desktop pcs are almost free compared to that...
