tomasm: the packaged driver in Fusion does not work well with F14 at the moment due to a bug in pyxf86config in Fedora, which means nvidia-config-display (in fact, all the -config-display's) doesn't run. That breaks configuration of the driver when using the Fusion packages, so if you install the Fusion NVIDIA driver packages, you wind up with a non-functional driver, at present. We (Fusion) don't really have a strategy to deal with this, yet. In practice, if you need the binary driver, installing it from upstream is probably the best method for F14 right now.
There is no 'preferred' driver exactly. It depends what your parameters are. If you mostly care about freedom, ease of updating, compliance with X.org standards, and support from the Fedora project, you want nouveau. If you mostly care about raw functionality, particularly 3D, VDPAU, and/or power management, you want the proprietary driver. My usual advice is to see if nouveau does the stuff you actually want to do with your computer, and if it does, use it. If not, go with NVIDIA.
tomas is right about the general question of keeping up with nouveau development; if that's your goal, you can better do it by running Rawhide or F15 (once it branches) than F14. Obviously, this has its own drawbacks.