Paul Thurrott has said that the current build of Windows Vista is 5384.3 and could be designated as Beta 2. However, he also said that a last-minute fix could cause the build to be 5385.
Windows Vista Beta 2 is going to be distributed at WinHEC next week. The most recent build that was released was 5381.1 which was very stable on my system. The Beta 2 release probably won’t have many bug fixes over the 5381 release but updated builds are always welcomed.
News Source: WinInfo