Finally, this day has came. Valve has released a stable version for Steam for Linux, that works on 64 bit systems.

To my mind, making Steam for Linux compatible with 64 bit is the best improvement ever.
This is a full list of improvements:
- Added support for 64-bit Linux titles
- Added a “friendly machine name” when Steam-Guarding an account
- Changed data format of client updates to improve compatibility with flawed proxy servers.
- During login, if Steam can’t be reached and the user has entered a username we’ve never seen before, pop a dialog and ask them to login again
- When returning to the login dialog and we’ve cleared the username field, put the keyboard focus on the empty username box instead of the password box
- Fixed failing to update a game properly if an unexpected folder exists in the install directory for a game and we want to replace it with a new file
- Fixed finding Steam client skins on Linux
- Fixed crash looking at community images on Linux
- Fixed Linux Steam overlay not restoring the proper mouse cursor in certain situations
- Fixed focus issue with the startup UI when the intro movie terminates early
- The play button on a games library page is now disabled if the game is not available on your platform
- Fixed updating background images in the library details view even when not visible while a game is running
- Fixed regression in prior update that made the Web/Friends footer buttons not appear in the in-game overlay on startup