Earth and Early Life, Nubia, Byzantium, Rome, and 20th Century Design are all scheduled to open later this year or early in 2010, as far as I know.
The Trypillians ( frightfully nice people - made lovely pottery ... ) vacated the Centre Block of Level 3 at the end of March, so that work on the 20th Century gallery ( and Byzantium, or whatever else is supposed to go in that space ) could begin. But the Egyptian Book of the Dead exhibition, to the west of that space, continues until October so I don't see how all of the World Culture galleries can possibly be finished this year. The Schad gallery was originally supposed to open in Winter 2008/09 but didn't.