Which free open source CPanel and WHM alternatives do you recommend/use? [closed]

http://www.anchor.com.au/hosting/development/we_hate_plesk_and_cpanel

If you need pretty front-ends for customer use, pick the best-of-breed ones for each individual task. Postfixadmin, for instance, for mail user use. They'll make far less of a mess of your system than any of the horrendous "all in one" control panels will, and allow you to keep administering the system properly, providing full flexibility to do what needs to be done.

ebox has been adopted by Ubuntu as the official config platform for ubuntu server. It has (I belive) a higher level view of tasks than webmin - task based rather than config file based.

On ubuntu hardy (8.04 LTS) it can be installed from the repositories, though apparently it is a bit broken in the gutsy and intrepid releases. More on ebox in ubuntu.