Life Support Myth
Don,
I agree life support is a key issue. However it is a myth we need vastly improved recycle systems. You only need greatly improved recycle systems if you are operating a closed system for 2.5 years. Mars has readily available oxygen and carbon though its atmosphere. Recent results also indicate water is readily available to provide water as is and O2 and H2 as well. Going to the Moon and working on the ISS will not help us learn to exploit these resiources. Focusing on going to Mars will. Neither the Mars reference mission or Mars Direct assume better life support systems than we currently have if I remember correctly.
In short, you can learn to improve life support systems on the Moon and ISS, but you don't need to.
Regards,
Mark