I think my response was a little flip and unclear at the beginning of this thread.
I just want to emphasize that having low gears helps tremendously and at my age I don't really care what people think of that. I always use the lowest gear I can, to feel comfortable. For example, on the ride I was leading Saturday, I had the chance to observe, as the sweep, what others do. What I saw was a lot of standing, painful looking mashing, zig zagging, sitting down in defeat and barely making it up the hill, which was not even that bad, in my opinion. I, on the other hand, had my triple in the granny and in the seond lowest gear on the back. I passed both of these riders with ease, and I was going at a nice pace for a hill. These riders were young and fit, so I ascribe it to technique. From what I see, people think it means thy're a wimp if they shift down. Sometimes I hear, "but I hate to shift."
As SheFly stated, I have seen 2.5 or 3.0 (in the Berkshires and in Spain) and I never felt like I was going to tip over. Just felt like the damn hill was never going to end.