Heh. The argument about protective filters has been raging for quite a few years :-) looks like it found its way to T4R boards :-D

My own position is kinda intermediate. If I am shooting on a beach or, say, in a dust storm I will make sure to put on a filter. It is *much* easier to wash off salt spray from a filter than from the front element.

If I am shooting in a situation where I care about the flare, I will take off the filter -- it's another air-glass-air transition and even though my filters are multicoated it's not doing any good for certain.

Otherwise I rarely bother. By default my "mostly outside" lenses have UV filters and my "mostly inside" lenses don't and that's how it usually works.