I think you've got the latest version. I think there might be 18.104.22.168, but I doubt that would be the fix.
Have you checked the threads on battery life? Closing programs and things like that?
Oh, one thing that was a complaint way back is with bluetooth on, battery life was extremely bad. It seemed like the phone would try to connect with anything bluetooth nearby. And I mean unpaired devices like other people's phones or bluetooth headsets. In my case my Playstation 3.