It is the new Western and Southern (et. al.) building and the first phase was completed about two years ago. If you'll notice, the first 8 floors or so of the first phase is parking garage to accommodate the parking capacity lost from the old garage. Through my perusings online, I've heard it mentioned that this tower is the real reason why the GABP "gap" was so architecturally featured. Most of the tower should be visible through the gap.
Here's a really good thread to read up on the developments. http://www.urbanohio.com/forum2/index.php?topic=3170.0
There are also lengthy threads on pretty much every proposed and ongoing Cincinnati development there (The Banks and streetcars included).