physx basically is ODE too. novodex just fixed all the (mainly collision detection) problems with it.

i would still wait a bit and see how this will turn out with nvidia. does physx still need this stupid 20mb driver?

maybe bullet or newton would be an option too but ODE really seems to be dead. there weren't any real fixes or improvements since a few years.

havok is all about the tools. the engine itself isn't much more advanced than other physics engines either.