Modern hard drives provide a means of telling the user if they are likely to fail called S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology). Although this is a de-facto standard no major operating system currently supports it out of the box.

While there are many S.M.A.R.T. tools for Windows included in system related products of third parties (e.g. Norton System Doctor) what somewhat raises the awareness of this problem, the only usable product for Linux is smartmontools.
The target group of this are, however, professionals. (This suite contains a command line tool and a daemon.)

Because hard drive failure is a often underestimated and neglected problem until it occurs, the user should be protected the best way without even knowing about it.

Therefore, I suggest to integrate smartmontools into Ubuntu in a smart and user friendly way. Providing a second barrier (besides backups) to hard drive failure.

Of course, the user is to be notified on dangerous situations by graphical means (e.g. a dialogue box, a message on login or in some not easily negligible way). To further ease rescuing the system, the user should be presented a "rescue wizard" allowing for easy bringing one's data to a safe harbour.