Going beyond cf, consider steel frames. At the entry level for good bikes, such as Surly, you'll mostly find butted cro-moly steel -- which is good stuff, but not metallurgically advanced. A bit higher up the price spectrum, you will get into some better grades of steel, and at the top end you will find the latest air-hardened and heat-treated steels such as Reynolds 853 and True Temper Platinum OX. The better grades of steel have a higher strength-to-weight ratio, and so the tubes can be drawn with thinner walls and still be sufficiently strong; air-hardened steels also grow stronger where they are heated up in the welding process, resulting in stronger joins. These higher grades of steel result in frames that are not just lighter, but often have a "livelier" ride quality, since the thinner walls (if used in the appropriate tubes) can both dampen road noise and feel more responsive.
The bicycle market is plenty competitive, which means that -- just as economic theory would predict -- you get what you pay for.