20090922 is just out, with a bunch of changes. The most noticeable of which is that Ctrl+Tab now behaves as it would in a typical Windows application, cycling through a stack of views. The old behaviour is still bound to Ctrl+Pageup and Ctrl+Pagedown.
The other significant change is that when overwriting files during the process of installing, any user-edited ones are now backed up first - these can be found in the Application Data/Sublime Text/Backup directory.
Otherwise it's a host of minor changes - the full list is on the beta page.