In this recent post to his site Sherif Ramadan looks at a proposal that's currently under view (RFC) to add the "finally" keyword to PHP.

It’s quite possible that PHP may finally be getting the addition of the finally block in its try/catch block. [...] It also solves a simple, but overlooked problem for the developer. With finally we offer the user-space code a chance to do any clean up work that may be necessary after a try block has terminated execution and with clear semantics.

He includes a use case for this feature - an example showing exception handling on multiple levels and writing to log files when the cleanup of the exception is finished (without the potential for another method to trigger the exception itself). "Finally" allows you to take this logic out of the exception handling and put it at the end, removing the possibility of it triggering an exception for the wrong reason. There's a few other examples showing some other quirks with its usage - like calling die will not make it end up in the "finally".