Just as a sidenote: I always used D3D, even on 1.5.1beta, but on the new version, 3D3 gives me a slideshow and I have to use OpenGl (which works perfetcly, so its no problem).
Phex, why not try the build mentioned on the previous page? See if it fixes your D3D problems as well. We're trying to make sure that it works across the board before we make a general release & replace the 1.5.1 app with it.