I actually solved it on my Sid install. Turns out with multiarch.. I couldn't get the 32bit nvidia GLX libs to install.. as they'd conflict with the 64 bit ones. Since I can't see the point in degrading to a 32bit system (hell, I'm not going to waste 12GB of ram)... I fudged things a little, grabbed the deb for the 32bit nvidia-glx libs.. symlinked them into the right spots and voila.. working!