I'm wondering what other peoples opinions are on this. I recently took a lot of shots for a friend for her business and I tended towards using ISO100 for pretty much the whole lot (using flash bouncing for lighting as needed).
Of course, when I passed these pictures on to a friend to have a fiddle with (read as: edit into being a more interesting picture =P), he noticed immediately that I was shooting almost exclusively at 100. He pointed out that he shoots primarily at 400 (sometimes at 800 as circumstances dictate), and that it's better to shoot at higher ISO as the noise level is more manageable. I think he also mentioned something about contrast, but this is me trying to remember a conversation from a week ago.
So what do you all shoot in? What is your favourite ISO for noise (or lack of it)?