The Alu/Steel thing... guess I'm coming from a perspective of not knowing any better. I bought my alu mtb cos it was a bike, and it was only £30 off someone at work, and it looked OK and felt nice to ride. I bought my alu roadie cos it was a roadie and I could afford the £300 or so it cost. Didn't even consider the materials.
For the sake of comparison, I like olive oil on my salad, or to fry onions in prior to making a pasta sauce. I would never dream of using sunflower oil for the same things. But I can understand why someone would say "well, it's oil, isn't it?".
So to all you steelies, I'm open to 'conversion', as it were, just never tried a steel bike (or I probably did when I was younger, I guess...)