MX962 lenses are expensive. While a bit of dirt may not be a problem why not look for some of the horror stories on this forum. One member I've read had a coke or coffee or something spilt on the front of the lens, I have smacked my camera lens first into a cliff hard enough to have a filter crack. No anti scratch coating would survive that I don't care what you say.
If you have something worth protecting protect it. If it's degrading performance because of shooting into the light then remove it.
I don't shoot into the light often and in
http://www.thephotoforum.com/forum/s...d.php?t=100830 this thread I have proved that a Hoya S-HMC does not produce any at all visible problems even with Nikon's Pro lenses under ideal conditions. So why would you NOT put a filter in-front of an L series lens.
As for what filter. I have a filter from each of the Hoya series. The standard UV and the HMC UV still produce notable degradation. The S-HMC is quite a wonderful filter and when looking into the front of the lens you can't notice the filter is there with a lens hood on.
As for the Pro1D that's just marketing smoke being blown up the collective asses of photographers. The width of an optical quality piece of glass has no impact into the quality of the light that is passing through at these small tollerances. All the problems filters cause happen mainly on the surface (reflections from lackof or poor coatings, refractions from uneven polishing). The prospect of designing a filter "specifically for digital cameras" is absurd snake oil.