Mac OS Rumors, a older rumor site which has lost much of its luster, gives details on the next update to Mac OS X, 10.4.4 build 8G17.
It should correct nearly 200 bugs, and should be much faster on dual processor machines, especially the latest dual G5s and the quad G5.
It should also bring new video drivers. We hope, in fact, that they really improve the latest NVidia cards, especially the Quadro. Because currently these cards use drivers that are not optimised for the old GeForce FX.