Seriously, all of the above, and anything except aluminum. I started there, and had problems with the harshness and vibrations hurting my hands, so went to carbon. Thought that was the best until I tried Ti. Have a ti/carbon mix and a full Ti, and love them both for long distance. Love the carbon for a faster/lighter climbing bike. Have two Italian steel frames waiting for me to build up. (Found one collecting dust in the back corner of a bike shop last week. What a find!)