A lot of it comes down to personal preference. While manufacturer's versions of drivers will sometimes give you added functionality (and this is becoming rare these days), the newer beta drivers will often give you better performance.
Since your card is based on the GF4MX GPU, you should have no problems using pretty much any of the Detonator drivers. A good source for these is
www.guru3d.com since they always have the newest beta drivers to hit the streets.
From there, just try out some of the newer versions and benchmark the system to see which gives you the best performance. Since the drivers will act in a unique manner in different systems, a little testing is usually necessary to get the best performance possible. :)