The Control-Alt-Backspace key combination to restart the X server was changed to the more unlikely combination Right-Alt+K+SysRq.  For some users, this key combination does not work.  I suggest that we change the default combination back to Control-Alt-Backspace as it is more user-friendly.

The following are some examples of the key combination Right-Alt+K+SysRq not doing what it is supposed to:

=====
Cheryl corrupted her filesystem because alt-printscrn/sysrrq-k conflicted with her download manager and deleted all her downloads.

http://www.ubuntugeek.com/restart-ubuntu-gnome-session-without-rebooting.html

=====
SaintDanBert could not use the key combination to restart his server, because it does not work with his keyboard layout.  Instead it launches a "storm of gnome-screenprnt commands."

bluemushroom also could use the key combination because of his keyboard layout.

http://ubuntuforums.org/showthread.php?t=1183156

====
For JohnE1, the key combination kills the X server but doesn't not restart it.  He also reports that it is similar to the key combination Ctrl + Alt + SysRq + B, which reboots the machine.

http://ubuntuforums.org/showthread.php?t=1183156&page=2

Some administrators have trouble getting back the old key combination of Control-Alt-Backspace.  Here is an example:

====
milomak reports that Control-Alt-Backspace does not work after setting "DontZap" to "false"

http://forums.debian.net/viewtopic.php?t=38046

Other users have expressed frustration over the change.

Conclusion:
The key combination to restart the X server should be intuitive, easy to remember, and work across a range of computers.  If the X server locks up then the user will be unable to google for the new key combination on his particular machine.  Experienced users will not know about the change until their X server locks up and Control-Alt-Backspace suddenly doesn't work.  For this reason, I suggest that we change the key combination back to Control-Alt-Backspace to be as user-friendly as possible.