I'm tempted to pick up one of these Ageia PhysX cards.
It would take a bit of load off my 8800. I had some difficulty running CellFactor too without additional hardware.
Team - Will the Unreal 3 engine and/or BioShock in general take advantage of advanced physics processing? I understand DX10 has some additional processing for physics, especially with stuff like water. I wanna be prepared.