The Steam Linux client is now available to everyone and with the Linux world not beginning and ending with Ubuntu, Valve's Linux developers are working to improve support for handling other distributions. Up to this point there's been mixed results when running Steam and the Source Engine games on other distributions due to packaging problems, graphics/driver issues, and other bugs.
In a Steam community posting, a Valve Linux developer says they're looking at improving the package dependency handling. They're looking at improving the install/update process of external dependencies by abstracting out the distribution-specific parts and moving it out to a separate file for easy handling by the distribution. Other ways for improvement are also being investigated.