The Windows 8 Beta blog reports that the latest Windows 8 build is 7996

We have earlier reported that Windows 8 build 7994 has been compiled, today our sources have told that Windows 8 build 7996 has been compiled with the full build string as 6.2.7996.0.winmain.110429-1810 which states that the build was compiled on April 29. Adding to it we have got some unconfirmed information that this build belongs to pre-beta stage and the beta stage would start from Windows 8 Build 8000.

  Windows 8 latest build, build 7996