The Windows 8 Beta blog reports that the latest Windows 8 build is 7922

Canouna has again updated the Windows 8 build list on MDL forums. According to Zukona the latest build is build 7922. The complete build string is 6.2.7922.0.winmain_win8m2.110202-1840 which states that the build was compiled recently on February 2.

  Windows 8 latest build, build 7922