Zero Install is designed to make the process of installing new software completely transparent. It achieves this by mapping a filesystem to HTTP. for example, if you wanted to install The Gimp, you would simply run it from
This idea, of breaking down the barriers between the local filesystem and the Internet to effectively eliminate the notion of installation definitely seems like the way forward. This is the kind of convenience that tools such as Debian's apt-get begin to provide - however 0Install takes it to its ultimate conclusion.
The next step, then, would be to build an entire Linux distribution around the 0Install principal. This would also benefit from upcoming filesystem innovations which allow set operations on directories (for example, having two directories and creating a new virtual directory that contains everything the two real directories do). At the simplest level this would eliminate things like the $PATH variable.
Creating a new Linux distribution that isn't afraid to make bold advances such as those outlined above will be the true next step in the evolution of operating systems - it won't be brain surgery, just elegantly combine a number of technologies (such as Linux, 0Install, and the new Reiser FS) that are already out there or in development.