PhaseOne, who purchased Microsoft Expression Media (originally iView MediaPro), has finally released a new version of the software under the name MediaPro. Read the MediaPro announcement on DPReview.com. You can purchase an upgrade from Expression Media 2 for US $59 directly from the PhaseOne website. It seems the major changes are (a) a new interface that closely resembles the CaptureOne image processing package, and (b) ability to use CaptureOne, Windows Image or Apple Core Image for rendering raw files. They have also added support for over 100 new cameras. Most notable is no more limit to 128,000 images and 2GB database size.
I have purchased my upgrade and will report back in a couple of weeks after I've had time to use it.